Seznam abstraktů 2019: POSTEROVÁ SEKCE B

Photocatalytic concrete screeds with self-cleaning and antimicrobial function have been developed and tested. These building materials contain sand grains with deposited composite TiO2/SiO2 layers. Two types of the screeds, grey and white, were prepared and their photoactivity and material characteristics were compared. Commercial TiO2 photocatalysts from several manufacturers were employed. Effects of different parameters, such as temperature of the coated sand calcination, humidity, and surface abrasion, were followed. Mechanical properties of the screeds were analyzed by SEM/XRD microscopy. Photocatalytic activity was tested by means of NOx oxidation (ISO norm 22197-1/2007). Antibacterial activity was evaluated by modified ISO norm 27447/2009 with Bacillus subtilis as a model organism.

Tungsten oxide is a perspective material for photocatalytic applications due to its relatively narrow band gap and stable physicochemical properties. Increasing the effective surface area of WO3 layers, for example, by its nanostructuring, allows increasing the effectiveness of WO3 photocatalysts. Anodization of W substrates was approved to be an inexpensive and effective method for nanostructured tungsten oxide production. However, there is still a lack of information about the appropriate regimes for ordered anodic WO3 formation and the effect of anodization and treatment parameters on the morphology and, eventually, photocatalytic and photoelectrochemical properties of WO3 obtained.
In this work, nanostructured WO3 layers were formed in NH4NO3-containing ethylene glycol-based electrolyte under a range of applied voltages. The morphology and chemical structure of this set of the samples were investigated. The samples were applied for photocatalytic degradation of methylene blue (MB), and the results were compared to MB photodegradation with nanotubular titania catalysts. The photoelectrochemical (PEC) properties were studied using a three-electrode system with quartz cell filled with 0.5 M Na2CO3. The stability of WO3 photoelectrode during the MB photodegradation and PEC experiments was examined.
This work was supported by RFBR grant № 16-33-60217 mol_a_dk.

In this study Sm2O3/ZnO and Eu2O3/ZnO nanostructures were prepared using microwave-assisted hydrothermal method. Effect of Sm2O3 and Eu2O3 content and calcination temperature was investigated. The reusability of obtained photocatalysts was also studied. The prepared samples were investigated by using XRD, X-ray spectroscopy, scanning electron microscope. The photocatalytic activity was determined by degradation of methylene blue (MB) under Osram Vitalux illumination. Modified ZnO nanoparticles according to XRD analysis consists of ZnO with crystallite size in the range of 16-23 nm. Under solar light simulated radiation prepared ZnO nanostructures shown high photocatalytic activity. After 30 minute of irradiation more than 95 % of initial MB solution was degraded. The photocatalytic test revealed that ZnO containing Eu2O3 and Sm2O3 exhibits higher activity than pure unmodified ZnO.

The photocatalytic degradation of dangerous substances is widely studied topic and many scientific reports have been already published about this issue. Undoubtedly, titanium dioxide is the most often studied compound for photocatalysis in UV region, while graphitic carbon nitride is the most often studied photocatalyst in VIS region. Combination of the photocatalysts leads to the formation of composites with improved photocatalytic performance and better applicability. In this work, the composites of exfoliated g-C3N4 and TiO2 in anatase form were prepared by mechanical mixing of both components in weight ratio 1:1. The prepared mechanical mixtures as well as the original components were thermally treated at 300 a 400 °C and characterized using X-ray diffraction method, infrared (FTIR) spectroscopy, UV-VIS diffuse reflectance spectroscopy (DRS). The morphology of the particles was studied using scanning electron microscopy (SEM). The photocatalytic activity of the samples was tested using the method based on the 2h long UV assisted photodegradation of Acid Orange 7. The results indicated the highest photodegradation activity for a non-thermally treated mechanical mixture of g-C3N4 and TiO2. For the composites the photocatalytic activity (PA) decreases with the temperature of the thermal treatment, the same effect was observed for original TiO2, while for original g-C3N4 the photodegradation activity increased with the temperature of the treatment.

Photocatalytic reduction of carbon dioxide (CO2) is a challenging reaction attracting a lot of attention. Finding a novel, efficient and relatively cheap photocatalyst is the goal of many research teams all over the world. Cordierite ceramic materials containing ceria (CeO2) nanoparticles show interesting photocatalytic properties. Five ceramic cordierite/CeO2 samples prepared from talc, kaolin, vermiculite/CeO2 nanocomposite with various amounts of CeO2 were investigated for the photocatalytic reduction of CeO2. Samples were prepared and characterized by X-ray diffraction method, specific surface area and nanoparticles CeO2 using transmission electron microscope. The photocatalytic activity of all samples was investigated in batch reactor irradiated by 8 W Hg lamps (254 nm). The main products of the photocatalytic reduction of CO2 were methane and carbon monoxide. Hydrogen was also detected, however, it is a product of water splitting, not CO2 reduction. Nevertheless, the presence of water is necessary for the reaction as water serves as hydrogen source. The cordierite/CeO2 samples containing CeO2 from 4 to 9 wt.% showed higher activity of photocatalytic reduction of CO2 than commercial catalyst TiO2 P25. The finding that lower CeO2 amount of 5.1 and 3.9 wt. % produced the highest photocatalytic activity is in an agreement with the literary results.

Dye-sensitized solar cells (DSSCs) are still considered as one of the prominent advanced technologies in the field of photovoltaics, next to perovskites, quantum dots, or organic solar cells. Dye molecules that have received considerable attention for application in DSSCs are donor-acceptor chromophores that provide high molar extinction coefficients, lower production costs, and smaller environmental impact. K.P. Loh et al. first reported the application of donor-acceptor systems for sensitization of diamond in 2008. However, photocurrents have remained still relatively low, recent record reaching 6 uA/cm2 by Kavan et al. In our work we aim to improve photocurrents of BNCD DSSC. We employ novel design and analysis of covalent BNCD-chromophore interface [RSC Adv. 8 (2018) 33276]. The functionalization by donor-acceptor DTP-BT chromophore was achieved through via electrochemical diazonium grafting and subsequent Sonogashira cross-coupling where donor part is grafted to diamond. While other functionalization methods lead to higher chromophore coverage, the Sonogashira method the resulted in 3x higher current densities (450 nA/cm2 at -0.2 V). By using Kelvin probe we found that the surface potential was homogenized by the chromophore grafting and Sonogashira cross-coupling provided the most pronounced photovoltage compared to other methods. Theoretical computing of diamond-chromophore structure, distribution of HOMO-LUMO orbitals, optical absorption and charge transfer by DFT corroborated these results. The work has been supported by GACR, FWO and CZ.02.1.01/0.0/0.0/15 003/0000464 (CAP) projects.

Thermal decomposition of complex salts [M(NH3)4]A (M = Pt, Pd; A = CrO4, Cr2O7) in oxygen atmosphere goes through the stage of formation of the phase MCrO2 with delafossite structure and it’s further decomposition and formation of the chromium oxide(III) and monometallic platinum or palladium. Thermal decomposition of complex salts [M(NH3)4]A (M = Pt, Pd; A = CrO4, Cr2O7) in hydrogen atmosphere proceeds with partial reduction of chromium to an metallic state and the formation of a metal solid solution MxCr1-x (M = Pt, Pd) with a chromium content up to 22 at.% and a chromium oxide(III). Catalytic properties of bimetallic Pt-Cr2O3 and Pd-Cr2O3 composites obtained by thermal decomposition in hydrogen atmosphere at the temperature 500 °C differs a lot from monometallic Pt and Pd in CO TOX and PROX processes. Addition of Cr2O3 boosted oxidative activity of metals probably due to appearance of metal-oxide interface, which is of crucial importance in catalysis.

In current, active investigations of anodic TiO2 nanotubes (TiO2 NTs) structures for environmental applications are provided due to its nontoxicity, large surface area, specific vertical morphology and semiconductor properties. Many studies dedicated to enhance TiO2 nanotubes absorbance spectra at the visible range by various doping methods or surface modifications (ionic implantation, thermal treatment, cathodic polarization, adding precursor to an electrolyte, anodizing alloy, immersing). However, previously was published anodic polarization method for boron doping TiO2 nanotubes [1]. Such method maybe used as perspective approach for easy TiO2-NTs doping also by other nonmetals e.g. sulfur.
In present work, influence of potentiostatic anodic polarization parameters in H2SO4 solution on morphology, geometry, crystal structure, composition, and photoactivity TiO2 NTs were investigated. Photoactivity of nanostructures was tested by photocurrent method. Samples of TiO2 NTs were fabricated by Ti foil anodizing in fluorine contain ethylene glycol based electrolyte. Morphology and geometry of nanotubes were investigated by SEM. Structure and composition of TiO2 NTs were studies by EDX, XPS and Raman spectroscopy.
REFERENCES: [1] Szkoda, M., Lisowska-Oleksiak, A., & Siuzdak, K. (2016). Optimization of boron-doping process of titania nanotubes via electrochemical method toward enhanced photoactivity. Journal of Solid State Electrochemistry, 20(6), 1765-1774. (DOI: 10.1016/j.materresbull.2013.05.023). ACKNOWLEDGEMENTS: This work was supported by RFBR grant № 18-29-23038 mk.

Structure, optical and photocatalytic properties for wide band gap oxide doped zinc oxide are investigated by XRD, ESR and UV-visible spectroscopy. It was shown the introduction of Al2O3 or ZrO2 led to form of structural defects in zinc oxide matrix. According ESR data a small amount of ZrO2 (0.01 mol.%) in ZnO forms a defects of donor nature, while the same amount of Al2O3 in ZnO matrix led forming as acceptor and as donor defects. Observed tail and shift of optical band gap confirmed ESR data. It was shown the increasing of donor defects in structure ZnO led to increase of photocatalytic activity to phenol degradation. It was shown the dopant types also determined a kind of intermediates of phenol degradation and possible mechanism. For Ag-decorated doped ZnO it is also shown that mechanism of phenol degradation contain a redox cycle. It was shown the bactericide activity of Ag-decorated ZrO2-doped ZnO to S.aureus is better than E.coli.

With the high level of air pollutants particularly in the cities the deteriorating conditions of the buildings accelerate. Bacteria, algae, lichens, mosses and fungi belong among the most important ones. One of the non-invasive and cheap ways how to prevent the buildings against the ageing processes is the innovation of suitable photocatalytic coatings. Our contribution focuses on the characterization of prepared photocatalytic nanocomposite TiO2-SiO2 system to be applied on the building objects in order to improve quality of their surfaces. It has been shown that composites based on nanostructured TiO2-SiO2 exhibit photocatalytic activity without remarkable reduction in intrinsic activity of bare TiO2. We developed a new type of such composite, structure of which is typical by presence of isolated islands of crystalline titania photocatalyst surrounded with SiO2 matrix. The SiO2 matrix is keeping units of aggregated TiO2 photocatalyst separated and can isolate the photocatalyst from direct contact with the substrate on which the material is applied. The entire composite structure is highly porous, allowing easy transfer of pollutants and their decomposition products inside in the composite material.

The aim of this study was to evaluate the possibility of the metallurgical wastes (slags and fly ash) utilization as a support for photocatalyticaly active composites. Metallurgical slags (MS) represent large volume group of by-products originated during the metallurgical production processes. The fly ash (FA) is the group of the wastes coming from the power plants, which are also part of the big cast iron and steel production plants. Although several applications of MS and FA already exist, non-negligible part is still stored in the landfills and thus the searching for new applications of these wastes is on high demand. Alkali activation of MS and FA represents one of the possibilities of the re-utilization of these wastes, which enables the application of these materials as the inorganic binders in building industry. The combinations of the photocatalysts with cement based materials are intensively studied with the aim of their utilization for the photocatalytic cleaning of the air. In present work, the alkali activated MS was tested as the matrix for the photocatalyticaly active composite kaoline/TiO2 and the alkali activated mixture of MS+FA was evaluated as a support the deposition of TiO2 layer. The photodegradation activity of prepared samples against NOx was tested. The results identified the application of TiO2 layer on the surface of alkali activated mixture MS+FA as favourable with respect to NO conversion.

Semiconductor-based heterogeneous photocatalysis is a promising technology for water and air purification without using consumables and generating harmful by-products. Bismuth molybdate as one of the simplest Aurivillius oxides with a narrow band gap of 2.7 eV has got wide attention due to its potential for photocatalytic applications. However, the inherent disadvantages such as a fast recombination of photogenerated electron-hole pairs and slow charge carrier transfer leads to low photocatalytic efficiency. Recently, it was reported that modification with lanthanides ions greatly improves the separation efficiency and migration rate of the interface carrier. Therefore, we report a simple strategy for synthesis Er3+/Yb3+/Gd3+ modified Bi2MoO6 vis hydrothermal method. The photocatalysts were characterized by diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and scanning electron microscopy (SEM). The photocatalytic activity of the powder samples was assessed by the degradation of phenol in the liquid phase under ultraviolet and visible light irradiation. To provide insight into the reactive inviduals participating in the degradation mechanism, a test with scavengers was also performed. The composite photocatalysts exhibit remarkable enhancement of the photocatalytic activity during photocatalytic phenol degradation as compared with bare Bi2MoO6. These excellent photocatalytic performances are ascribed to the synergistic effects of the extended visible light response, and improved separation efficiency of the photoinduced charge carriers.

A simple and ecofriendly facile route for the efficient hydrogen transfer reaction under visible light is demonstrated here via photo-catalyst Pd(0)g-C3N4. The photoactive catalyst synthesized by incorporating ultra-nanoparticle (< 5nm) palladium over graphite carbon nitride (g-C3N4) semiconductor using formate solution as reducing agent and Pd(0)g-C3N4 efficiently perform photocatalytic transfer hydrogenation of various aldehydes and ketonic functional groups selectively with different alcohols. A synthesized catalyst Pd(0)g-C3N4 exhibits good to excellent reactivity in visible light with quite mild reaction conditions. The physicochemical properties of the photocatalyst were analyzed by XRD, FT-IR, XPS, UV-visible, tauc plot, HRTEM-HAADF elemental mapping, EPR detailed characterization techniques. High conversion (upto 98%) selectivities (upto 99%) and recyclability was well attained via photoactive catalyst Pd(0)g-C3N4 along with noteworthy benefits; to handle in blue LED light (visible light-setup), solvent free no heating, non-toxic, environmentally friendly and very short period span 3 h with appreciable product selectivity (99% selectivity ~99% yield). Finally, the photo-catalyst Pd(0)g-C3N4 shows well maintained molecular structure evidenced by XRD, XPS, IR, TEM and ICP-MS analysis etc., even after many reused many times, without a major loss in activity. In detailed performed EPR measurement, in the presence of N-tert-Butyl-a-phenylnitrone as a spin trap agent, g-C3N4 material under irradiation, display well here the photoactive semiconductor nature due to localized π states of g-C3N4. Further the photocatalytic hydrogen transfer reaction mechanism in the presence of N-tert-Butyl-a-phenylnitrone as a spin trap agent, clearly confirmed the formation of isopropyl radical (CH3)2COH●, plausible mechanism is proposed for hydrogen transfer of carbonyl group on the basis of EPR detailed study.

The electrocatalytic activity of gold nanoparticles (AuNPs) in oxygen reduction reaction (ORR) is of great interest, particularly in the field of fuel cells. Investigations show a remarkable influence of different factors such as pH, nature of support, as well as particle size, shape and crystallographic orientation on the kinetics of ORR on AuNPs electrodes. The surface ligands used for stabilization of AuNPs also can tune their ORR activity. Herein, we deposited chemically prepared citrate- and tetrazole-stabilized AuNPs onto TiO2 nanotubular layers (TNT) and evaluated the activity of obtained AuNPs -TiO2 systems toward ORR.
In oxygen-saturated alkaline solutions, ORR on the bare TNT electrodes is observed as an irreversible peak/wave at potentials more negative than -0.65 V. After deposition of citrate-stabilized AuNPs onto TNT, an additional wave related to ORR on the gold surface appears at less negative potentials. The position of this wave is strongly depended on the surface concentration of AuNPs. The overpotential for O2 reduction on the gold surface decreases with increasing the amount of deposited AuNPs.
The tetrazole-capped AuNPs are almost inactive for ORR. The covalent interaction between gold and thiol groups of 1R-tetrazole-5-thiol greatly inhibits the chemisorption of O2 and leads to inactivation of the AuNP surface. Thermal treatment and potential cycling were applied to remove the surface ligands from AuNPs and to investigate the role of surface coverage of ligands on the catalytic performance. Effective removal of the ligands from the gold surface by these methods results in activation of the AuNPs-TiO2 electrodes.

Photoelectrocatalytic (PEC) conversion of CO2 has been extensively investigated in past years as it uses the solar energy to combine CO2 and water to produce hydrocarbons. In the present work, B@g-C3N4/PANI nanoblend was synthesized by in-situ polymerization of aniline in presence of B@g-C3N4 for PEC CO2 reduction. The catalysts were characterized by TEM, XRD, UV-visible absorption spectroscopy, photoluminescence (PL), XPS and Mott-Schottky analysis. The photoelectrocatalytic activity were evaluated by LSV and chronoamperometry. XRD revealed the formation of g-C3N4 where as the doping of B was confirmed by XPS. The presence of PANI was confirmed and visualized by FTIR and FESEM respectively. A remarkable cathodic current associated with CO2 reduction was observed during LSV from onset potential of -0.01 V vs NHE which was comparatively more positive than the B@g-C3N4 (-0.82 V vs NHE) and the positive shift is attributed to the slow charge recombination kinetics of the B@g-C3N4/PANI as evidenced by PL and EIS results. The incident photon-to-current efficiency (IPCE) reached a value of 19% at 420 nm using an applied potential of -0.3V vs NHE. The PEC system was run at -0.3 V vs NHE under light illumination (420 nm) for 4 hr and the product in the liquid phase was analyzed. Methanol was found as sole product in liquid phase under these conditions with quantum efficiency of 8%. The stability and reusability of the catalyst and the mechanism of PEC CO2 reduction are investigated and discussed.

Nowadays, global warming represents significant ecological problem. The crucial aspect is the increasing concentration of greenhouse gases (especially CO2) in the atmosphere. [1] Possible solution could be assigned to the lowering concentration of CO2 by conversion into more valuable compounds. [2] For this purposes, iron-based materials demonstrate one of the most effective catalytic material for hydrogenation of CO2 to methane, methanol and another simple hydrocarbons. [3]
This study focuses on catalytic hydrogenation of CO2 in the gas phase. The reactions proceed at low pressure of 1 bar and the temperature of 325 °C on the catalysts. These catalysts are prepared samples of mesoporous iron oxides with a high surface area. All prepared catalysts are produced CH4 by conversion unlike the commercial Fe2O3 used as reference. By-products of reactions are CO and H2O. The catalytic activity is different for each sample and relates to a presence of Fe3C phase in prepared catalysts.
ACKNOWLEDGEMENTS: Authors thanks for financial support from internal grant of UP Olomouc project IGA_PrF_2019_033.
REFERENCES: [1] M. Áresta, A. Dibenedetto, Utilisation of CO2 as a chemical feedstock, Dalton Trans., 2007, 28, 2975.; [2] A. Rafiee, R. Khalilpour, D. Milani, M. Panahi, Trends in CO2 conversion and utilization: A review from process systems perspective, J. Environ. Chem. Eng., 2018, 6, 5771.; [3] C.-S.T. Chih-Hung Huang, T. Chung-Sung, A review: CO2 utilization, Aerosol Air Qual. Res., 2014, 14, 480.

The paper deals with simulations of the distribution of electric field on the collector surface during the DC-electrospinning process. The object of the simulations was to find out whether it is possible to achieve a uniform distribution of the electric field on the surface of the circular collector. The homogenity of the nanofiber layer formed on the collector is related to the uniformity of the distribution of the electric field. Simulations were performed for different shapes of the circular collector, where the geometry of the collector edge was changed. From the simulation results it was found that a suitable adjustment of the collector edge geometry has a significant effect on the distribution of the electric field on the collector surface.

Photo-sensing is a feature widely used in many professional and consumer systems, such as fiber optic communications, solar cells, and so on. They all rely on the same process: transform a light power into an electrical signal. The objective of this article is to present the results of a theoretical simulation evaluating the concept of InGaN-based solar cell, in order to determine the impact of these materials on the efficiency of solar cells, as well as it’s provided a benefits. A detailed study of the InGaN heterojunction-based photovoltaic cell was carried out on its structure, its characteristics, its physico-technological parameters and the comparison with other structures with different alloys based on InGaN / GaN and AlGaN / GaN. Overall, the results confirm that InGaN represents the best choice in the field of photovoltaics and renewable energies in general.

Perovskite solar cells (PSC) represent one of the most attractive research topics in the field of alternative energy sources. To achieve better performance of the cells, both in terms of efficiency and stability, engineering of interfaces between individual layers has a crucial role. It has been already shown that incorporation of organic material-based interlayers between perovskite layer and electron transporting layer of inverted PSC can significantly improve their performance. Diketopyrrolopyrrole (DPP) based semiconductors are interesting candidates for such application. These materials have been widely applied in various optoelectronic devices and therefore it is expected that they can possess desired properties. Moreover, use of DPP based pigments can offer possible enhancement of stability due to their inherent hydrophobic nature, thus can form a shield against moisture invading perovskite material.
In this study, electronic properties of newly synthesized DPP pigments were investigated using cyclic voltammetry and charge carrier mobility measurements. Charge extraction abilities of used materials were studied via steady-state and time-resolved photoluminescence measurements of perovskite combined with the pigment. Selected materials were subsequently introduced into perovskite solar cell structure in form of thin film interlayer prepared by vacuum deposition. The improvement of perovskite solar cells’ performance was assessed by measuring their I-V characteristics under illumination.

In this work, solution-processable graphene oxide (GO) dispersions were used for the simple preparation of thin GO layers (50 nm thickness), which were reduced by low-temperature hydrogen plasma. Hydrogen plasma reduction (ideal treatment time 8 sec) led to a decrease of oxygen-containing groups and consequently, in the transformation of sp3-carbon oxidized domains to preferable sp2-carbon aromatic domains in rGO layers (XPS). GO and rGO layers were used as counter-electrodes (CEs) in printed dye-sensitized solar cells (DSSCs). DSSCs with rGO CEs reached an increased conversion efficiency of ƞ = 0.9 % compared to DSSCs based on GO CEs with ƞ = 0.4%. This can be attributed to the higher catalytic activity of plasma reduced rGO CEs in the presence of iodine electrolyte and also lower sheet resistance (˂100 MΩ/□) compared to GO CEs.

Currently polymer and small molecules bulk-heterojunction organic solar cells exceeding 16% power conversion efficiency attracted particular interest due to their flexibility, color tunability and predominantly potentially low production cost. In this work, we investigated several diketopyrrolopyrrole (DPP) derivatives as potential donor materials for fullerene:DPP solar cells. Several strategies were applied to modify DPP molecule. DPP properties were tuned by introduction of various polar substituents or by introducing a nitrogen atom into the terminal moiety of the molecule. The enhanced solubility was achieved by N-alkylation. Our quantum -chemical calculations predicted that this modification would increase the rigidity of the molecular structure and increase the ionization potential relative to the original DPP derivatives. The higher ionization potential primarily supports an enhancement in the open circuit voltage, and a more rigid molecular structure will contribute to reduced nonradiative losses. We experimentally verified the fullerene:DPP solar cell concept based on the coincidence of a smaller driving force for charge separation at the donor/acceptor interface and the crystallinity of the studied DPP derivatives for preparing effective photovoltaic devices. The reduction of the driving force for charge separation could be overcome by more structured/packed donor DPP materials; the delocalization of electrons and holes in such structured materials improves charge separation in OPV devices. Using wide range of experimental methods, we determined the parameters of the studied DPP materials with PC70BM in thin films. This work contributes to practical applications by verifying the concept of this organic solar cell design.

Nanocarbon materials such as carbon nanotubes and graphene can show excellent photothermal properties due to the localized surface plasmon resonance of the nanomaterials. In particulalr, nanocarbon hybrids composed of zero-dimensional nanodiamond, one-dimensional carbon nanotube, and two-dimensional graphene may exhibit enhanced photothermal properties as well as higher electrical and thermal conductivities. In obtaining the nanocarbon hybrids, covalent and non-covalent functionalization methods have been widely used. Covalent functionalization is often more advantageous compared to non-covalent functionalization because of better bond connectivity and interaction between nanocarbons, whereas the noncovalent functionalization gives no change in the carbon structure of the nanohybrids. In this study, the graphene based nanohybrids including carbon nanotubes and germanane were prepared using covalent or non-covalent functionalization, where germanane as a new two-dimensional nanomaterial has a very high electron mobility compared to silicon. The nanohybrids of graphene and carbon nanotubes were synthesized using a click chemistry reaction, and the nanohybrids of graphene and germanane were prepared in non-covalent functionalization using the polymer-grafted graphene oxide. The photothermal properties of the nanohybrids were measured by irradiating a near infrared laser, and the photothermal properties of the nanohybrids based polyurethane films were also investigated. Structure and morphology of graphene based nanohybrids were analyzed. The synergistic photothermal properties of polyurethane based composite films as well as nanohybrids were found. It indicates a potential application of graphene based nanohybrids for excellent photothermal nanomaterials and use as photo-actuators.

Carbon dots (CDs) owing to their green and cheap nature, high absorption coefficient and tunable optical properties, are promising emitters for solar harvesting devices. In the effort of reducing the solar electricity cost, luminescent solar concentrators (LSCs) have attracted noticeable attention during the last years. Because of their low cost and semi-transparency, LSCs could cover facades of urban buildings thus creating energetically self-sustainable units. Here we present the fabrication of a large-area (8×8 cm) LSC by employing green-emitting CDs. Despite a high transparency over the visible spectrum (average transparency of 91.6%), the fabricated device shows internal and external quantum efficiency of 33.3% and 1.5%, respectively. Due to these key merits, the fabricated LSC presents new opportunities for advanced solar light-harvesting technologies.

CoWO4 is predicted to be a very promising electrode material for supercapacitors. In this study, a novel flower-like morphology of CoWO4 fabricated by a hydrothermal method is presented for the first time. The prepared CoWO4 have been thoroughly characterized by scanning electron microscopy and X-ray diffraction. The special CoWO4 nanostructure exhibits noticeable specific capacitance of 156 F·g-1 at 0.5 A·g-1 and shows outstanding rate capability (85.2% capacitance retention at 10 A·g-1). The proposed feasible route is expected to be applied prospectively and widely in preparing CoWO4 pseudocapacitive material, which owns great application value in supercapacitors.

We have developed an inexpensive and efficient technology of hydrothermal growth of ZnO nanorods from zinc nitrate hexahydrate (Zn(NO3)2·6H2O), as a precursor and hexamethylenetetramine (HMTA) (C6H12N4), as a surfactant followed by plasma hydrogenation in a novel inductively coupled plasma (ICP) quartz reactor and equipped with the rotary sample holder to stir powder during plasma treatment. We have optimized the photoluminescence spectroscopy for measuring optical scattering samples with the high sensitivity, precise sample positioning and very low influence of the scattered excitation light. Here we present the latest results on the enhancement of the UV photoluminescence of the ZnO nanorods after plasma hydrogenation. The exciton-related photoluminescence has been significantly enhanced whereas the deep defect related yellow photoluminescence has been significantly decreased.

Investigations of kesterite Cu2ZnSnS4 routinely encompass work on efficient synthetic routes and, quite intentionally, focus on the material’s semiconducting properties that are crucial in making it an active component in second generation photovoltaic cells. In this regard, the mechanochemically assisted synthesis of kesterite is an attractive way to get an inexpensive and good quality product.
In this study, kesterite was prepared by a two-step synthesis route. In the first step, a suitable mixture of the sulfides Cu2S, SnS, ZnS and sulfur S was mechanochemically reacted in a high energy ball mill for 20 h at 900 rpm with xylene as a dispersion liquid. The second step included annealing of the raw solid at 500 and 550 °C for 6 h under an argon flow. All materials were examined by XRD, UV-vis spectroscopy, Raman spectroscopy, 65Cu/119Sn MAS NMR, and XPS. The magnetic properties were determined by a SQUID magnetometer.
The raw powder after milling showed a cubic sphalerite-type structure (pre-kesterite) and no semiconducting properties whereas it was characteristic of a relatively strong ferro- and paramagnetism. The annealing at 500 and 550 °C caused the transformation of the cubic pre-kesterite to the tetragonal kesterite. The annealed powders had the band gaps corresponding to the reference value (Eg = 1.4-1.5 eV). Interestingly, the ferromagnetic phase was no longer present and the paramagnetism was much weaker. The main factors responsible for the correlation of semiconductor and magnetic properties of nanopowders in this system could be linked to the type and extent of nanocrystallite defects. ACKNOWLEDGEMENTS: Funded by AGH-UST Research Subsidy for young scientists No. 16.16.210.476.

In this work we demonstrate how simultaneous photocurrent and Raman spectroscopy measurements can be used to locate and identify defect regions in single crystalline silicon solar cell modules. We also utilise Raman spectroscopy to look at the stress distribution in individually encapsulated silicon solar cells laminated under varied conditions (encapsulant material, encapsulant layer thickness, interconnect soldering).
Raman spectroscopy is a non-contact, non-destructive analytical technique that provides sub-micrometre information on the vibrational, crystal and electronic structure of materials. It is the ideal method for investigating solar cell materials including the different forms of silicon and perovskites and can be used to determine, crystal quality, stress/strain and electronic properties. Recent advances in instrumentation has made characterisation of these materials easier and more comprehensive, adding features such as ultrafast mapping (>1000 spectra/s) and automatic sample focus tracking capabilities.
When collecting Raman spectroscopy data, a laser source is shone on the sample surface, which in electronically connected devices may create a photocurrent. When collecting a Raman map of a sample the laser is rastered across the sample surface and by continuously measuring the photocurrent we can create a corresponding photocurrent map to go with the Raman map. This photocurrent map allows defected areas, where the laser induced current is lower than average to be visualised, and the corresponding Raman data can be used to better understand the root cause.

The work is focused on the assessment of mutual influence of group of spinning electrodes placed in one plane in dependence on their mutual distance, during AC-electrospinning. From the results of the experiment it was found that the distance between the electrodes affects the stability of the nanofiber production process and the siding behavior while AC-electrospinning. In the first phase of the research, simulations of electric field distribution around spinning electrodes were performed. The results obtained by the research will serve for a suitable choice of design parameters of the device for production of flat nanofibrous textile by the AC-electrospinning method to achieve the required width of the nanofibrous textile.

Polyhydroxybutyrate (PHB) nanofiber mats - pure PHB control, loaded with nanoparticulate titanium dioxide or zinc phthalocyaninine derivative, and with combination of both the photocatalytic agents - were prepared by the centrifugal spinning technology and characterized. Photocatalytic efficiencies of the nanofibers mats were tested for degradation of gaseous pollutants, such as acetaldehyde, according to the ISO 22197 standards. Long-term stabilities of the prepared photocatalytic nanofiber mats were also analysed.

PMMA / PTFE optical fibers with increasing lateral emission were coated with titanium nanolayer using low-temperature plasma. We investigated how this nanolayer affected the spectrum of emission when VIS LED and UVA LED light sources were used. Even though the FTIR analysis didn´t confirm the presence of TiO2 in the titanium nanolayer, the fibers exhibited significantly higher antibacterial properties compared to non-coated fibers. If we don´t assume that the titanium surface itself has antibacterial properties, the cause of this phenomenon is in the properties of the formed surface structure. Nevertheless, this treatment could extend the use of polymer optical fibers (POF) to new applications, such as illumination of infectious areas, for example, hospital corridors.

Increase in electrical conductivity arising from ordering of polyaniline (PANI) chains when combined with phyllosilicates, e.g., montmorillonite (MMT), was reported in recent years. However, conductivity monitoring over a long-time period, which is essential for practical use of these nanocomposites, is still not commonly studied. This study deals with the preparation and long-term measurement of the electrical conductivity of PANI and PANI/MMT nanocomposite layers. PANI thin layers were prepared from anilinium sulfate using ammonium persulfate as an oxidizing agent. The polymerization was carried out in aqueous suspension at room temperature under stirring for 20 minutes. In the same way except that 0.2 g of MMT was added to the reaction mixture during polymerization, a thin PANI/MMT layer was prepared. This layer was synthesized for 4 hours.
Electrical properties of the samples were studied for thirteen weeks. The conductivity of the pure PANI layer was 182 S/m at the beginning of the measurement and 9 S/m at the end. For PANI/MMT layer, the conductivity at the beginning of the measurement was 1942 S/m and 428 S/m at the end. The conductivity of PANI/MMT thin layer was found to be higher compared to pure PANI layer. This increase can be attributed to the alignment of PANI chains anchored on flat MMT particles. The structure and the properties of samples have been characterized using combination of X-ray diffraction analysis, atomic force microscopy, and Raman spectroscopy. ACKNOWLEDGEMENTS: This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic (project no. SP2019/31).

Present work is dedicated to the development of lithium-nickel oxide film - positive electrode for solid-state lithium-ion batteries. The formation of electrochemical phase was performed by а two-step process. At first lithium-nickel oxide film was deposited by Atomic Layer Deposition on stainless steel 316SS and silicon wafer at 300 °C. One “supercycle” of lithium-nickel oxide film consisted of n (5 or 10) cycles of nickel oxide structures (NiOx) deposition, followed by one cycle of lithium oxide (LiOx) structures deposition. Bis(cyclopentadienyl)nickel(II) (NiCp2) and Lithium bis(trimethylsilyl)amide (LiHMDS) were used as metal precursors. Oxygen remote plasma was applied as a counter-reagent (oxidizer). The thickness of deposited films was 58.2 nm (n=10, 250 supercycles) and 74.3 nm (n=5, 500 supercycles). At the second step, the obtained films were annealed in an air atmosphere at different temperatures 400-800 °C for 10-15 minutes. Spectral ellipsometry, small-angle X-ray scattering, X-ray diffraction were used to characterize obtained films. The electrochemical performance was studied with the use of Cyclic Voltammetry and Galvanostatic cycling. The discharge capacity augmented with an increase of a fraction of NiOx structures and annealing temperature. The highest capacity (23 µAh·µm-1·cm-2, at 7.4C rate) was observed for sample calcined at
800 °C (n=10, 250 supercycles).

Tribological coatings are mainly used to reduce adhesive wear, which often leads to the seizure or the formation of cold welds. The low coefficient of friction and good sliding properties make it ideal for applications with low lubrication or even dry running. The result is an ideal way to reduce surface fatigue and tribo-oxidation. Tribological coatings have good sliding properties, a low coefficient of friction and low adhesive wear. Thin layers of WC/C and TiC/C of the MeC/a-C: H coating group were deposited onto the surface of ISO 683/11-70 steel. The third tribological coating deposited on the same substrate was a ta-C coating - a tetrahedral amorphous layer (stoichiometry: sp3 bonds > 50%). Tribological measurements were performed at a load of 10 N, a rotational speed of 60 rpm, and with a counterpart of ceramic material Al2O3.

The development of micro- and nanoscale power sources for micro size electronic devices such as wireless sensors, biomedical implants, and smart cards is an important task. In this work, the processes of synthesis uniform lithium oxide, cobalt oxide, and lithium cobalt oxide thin films using atomic layer deposition (ALD) method were studied. Lithium tert-butoxide (LiOtBu) and cobaltocene (Co(Cp)2) were used as precursors. Remote oxygen plasma was used as a counter-reagent. The synthesis was carried out at 300 °C. The growth rate and uniformity of the films were controlled by adjustment the precursor's evaporation temperature, reagent pulse time, and purge times. Monocrystalline silicon and stainless steel (SS316) were used as substrates. The films were studied by spectral ellipsometry, energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction analysis (XRD). Results showed that an increase the purge time to 10 s after the reagent pulse positively affects the uniformity of the films. The growth rates of Li-O and Co-O systems were 0.080±0.010 nm/cycle and 0.022±0.003 nm/cycle, respectively. XRD data showed the presence of the crystalline CoO phase for the Co-O and the presence of the LiCoO2 for Li-Co-O samples. The optimized synthesis parameters determined for Li-O and Co-O were subsequently used to synthesize Li-Co-O (LiCoO2-x) system. According to the growth rates of Li-O and Co-O, the ratio of Li and Co pulses was set as 1/5. XRD data showed well crystalline LiCoO2 textured in (003) direction for as-deposited Li-Co-O thin films. According to cyclic voltammetry (CV), there is a pronounced peak characterizing of the change in the oxidation state of cobalt from 3+ to 4+. Based on cyclic tests, the Li-Co-O films have high coulombic efficiency.

WO3@ BiVO4 heterojunction thin films are prepared 1-dimensionally by combining a flame vapor deposition (FVD) process with spin coating method. The FVD system is a rapid, economical system for thin film growth and is incorporated with a controllable wire feeder for precise feed rate. The 1-D sub-stoichiometic tungsten oxide nanowires are grown in FVD process. These flame synthesized WO3 nanowires provide high interfacial contact area to coat the BiVO4 shells. The WO3@BiVO4 heterojunction thin film displays the individual strengths of WO3 (good electron transport property) and BiVO4 (strong light absorption) photocatalysts and exhibits superior performance in photoelectrochemical (PEC) water splitting under back illumination. The thickness of WO3 nanowires can be controlled easily and the optimal thickness of WO3 nanowires is proposed for best-performing nanostructured WO3@BiVO4 thin film in PEC water splitting. This WO3@BiVO4 photoanode prepared in this study provides quite reasonable photocurrent under simulated solar light back illumination (100 mW/cm2). This study proposes a promising practical method to prepare 1-D WO3 based composites photoanode for PEC water splitting.

Zinc oxide is multifunctional material which can be used as polymer additive. Here we present using ZnO nanoparticles in polymer matrix for piezoelectric sensor applications. However, for optimal results, it is necessary to manage synthesis of different morphology. We report method of ZnO synthesis by precipitation from aqueous solutions of zinc acetate by OH- ions. We have studied, how synthesis parameters can affect product morphology and composition and its performance in composite. We can effectively prepare different particle shapes of pure ZnO with high yield. Synthesized ZnO and prepared composites were studied by SEM (size and morphology of particles), XRD (phase identification, crystallite size).

Cellulose, as the most abundant polymer in the world, and recently nanocellulose, have emerged as sustainable, biodegradable and recyclable substrates for flexible and printed electronics in applications that require rapid roll-to-roll manufacturing. However, the wetting and printability of any material surface are linked to its surface energy. These may be modified by cleaning and activation of the surface, i.e. removal, formation or alteration of the adventitious or functional chemical groups on it. Recently, novel surface treatment techniques compatible with roll-to-roll manufacturing have attracted considerable attention on the part of researchers. In this contribution, we present atmospheric-pressure plasma generated by diffuse coplanar surface barrier discharge (DCSBD) for the surface treatment of nanocellulose transparent paper. The effect of ambient-air, low-temperature plasma on the surface of nanocellulose was investigated. Water contact angle measurements revealed increased hydrophilicity of the surface after short plasma treatment. X-ray photoelectron spectroscopy was utilized for chemical analysis of the surface of the nanocellulose. Plasma treatment led to a decrease in carbon concentration and a corresponding increase in oxygen concentration. Analysis of carbon peaks in the spectra revealed decreased C-C bonds and the formation of oxygen polar groups. The formation of polar groups was directly related to the increased hydrophilicity. Scanning electron microscopy was used to observe the morphological effects of plasma treatment on the nanocellulose surface. No damage to the nanocellulose fibres was observed after plasma treatment, which confirms that low-temperature plasma is suitable for large-area roll-to-roll treatment of nanocellulose.

In the present time germanium nanowires (GeNWs) shows great interest among the science community. Due to the excellent electrophysical properties such structures can be used in energy storage and generation applications and optoelectronics. However, the technological complexity of nanostructured Ge manufacturing process limits its production. Recently, a new method of preparing crystalline filamentary Ge nanostructures has been proposed. Described method based on electrochemical deposition of Ge from aqueous solutions at room temperature. In this case liquid metal nanodroplets that have low melting points, such as Hg and Ga, are used as an electrode.
In this paper, we demonstrate a simple method of GeNWs formation by electrochemical deposition from aqueous solutions at room temperature using In nanodroplets as a nucleation centers. Indium nanoparticle arrays are formed by vacuum thermal evaporation and condensation of evaporated material small batches using molybdenum vaporizer. This method allows controlling the density and size of In nanoparticles, which in turn makes possible to control the dimensions of the GeNWs. This work presents results of particle size indium influence on the obtained Ge structures morphology. The results show that the nanowire length and diameter depends on the In nanoparticle size. The lower In nanoparticle size, the lower diameter and maximum length are Ge nanowire will have after the deposition process. Thus the size of the In nanoparticle determines the maximum length and the initial diameter of the Ge nanowire. In order to fit the experimental data, we have proposed a simplified model and adapted it to our growth conditions.

Polypropylene (PP) is widely used in diverse applications including packaging, plastic parts and reusable containers. Although PP shows high resistant to a wide range of solvents, PP-based products suffer from low resistance to flammability and tend to thermally decompose when exposed to ultraviolet radiation, at high temperatures or in oxygen-rich environment. During the last decade the introduction of nanoadditives into polymers resulted to competitive products with improved critical properties. In this study, Mg(OH)2 nanoparticles have been evaluated towards increasing PP resistance to thermal degradation. Mg(OH)2 nanoparticles with different sizes (ranging from ~25 nm up to 2 μm) were synthesized by a simple scalable precipitation method using different precursor salts. In order to improve their compatibility with PP, organically modified Mg(OH)2 particles were also synthesized, following the same procedure in presence of different hydrophobic organic molecules. The structure, morphology and thermal properties of Mg(OH)2 particles were studied by several characterization techniques like X-ray diffraction, infrared spectroscopy, thermal analysis and electronic microscopies. PP/Mg(OH)2 nano-composites were prepared by a solution-precipitation approach. We studied the effect of different parameters, i) particle size, ii) % loading of nanoparticles and iii) with or without organic modification, in the improvement of thermal stability of resulting PP composites.
AKCKOWLEDGEMENTS:We acknowledge support of this work by I) the project MIS 5002772, implemented under the Action “Reinforcement of the Research and Innovation Infrastructure”, funded by the Operational Programme "Competitiveness, Entrepreneurship and Innovation" (NSRF 2014-2020) and co-financed by Greece and the European Union (European Regional Development Fund) and II) the project ΑΜ1ΧΠ-00009 under the framework of Regional ESPA 2014-2020 funding scheme (co-funded by Greece and EU).

The measurements of volatile organic compounds are becoming more important due to stringent environmental regulations and increasing health concerns. The human breath which includes many volatile organic compounds that can be used as biomarkers for different diseases as well. Metal oxide (MOX) sensors are well known as multifunction nanomaterials and employing MOX in detecting VOCs is one of the most studied areas. The advantages of metal oxide sensors are well known as low costs, short response time and versatility. Currently, these sensors are sufficiently sensitive for most applications. However, the use of them is limited due to their lack of selectivity, which has stimulated researchers to look for different strategies to overcome this drawback. Sensing mechanisms of gas sensors depend on temperature, and this is, in particular, true for metal-oxide semiconductors where the peculiar role of temperature suggested the modulation of temperature as a viable method to tune selectivity and sensitivity. In this work, a device consisted of metal oxide gas sensor array has been used to discriminate different volatile organic compounds. The device consists of three MOX commercial sensors (ASMLN, AS-MLK, AS-MLC), The behavior of these sensors was measured at different ranges of temperature. By Principal Component Analysis (PCA) as a recognition algorithm and modulated temperature, selective sensing has been accomplished.

Facile and large-scale synthesis of well-performing supercapacitor electrode material is urgently needed all around the globe. Here, we present the supercapacitor properties of graphene acid (GA), covalently functionalized graphene derivative, as suitable electrode material for energy storage applications. We have studied the performance of GA in the presence of two electrolytes: 1 M sulfuric acid and 1 M sulfuric acid with 0.005 M hydroquinone using cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy in three electrode setup and in two electrode setup (full device). Moreover, we show the high reproducibility of the actual synthesis as well as the stability of the material over time in air atmosphere with respect to electrochemical performance. GA exhibits higher capacitance in the presence of hydroquinone, as opposite to the cyclic stability at 3 A/g, potential window 1 V, lasting 100 000 cycles in sulfuric acid only and 30 000 cycles in sulfuric acid with hydroquinone, both with retention > 93%.

Two powdered wastes originating in building materials production (waste brick dust (WBD) from the production of ceramic blocks and concrete slurry waste (CSW) from prestressed poles production used also in Fe-modified form (CSWFe)) were studied as potential adsorbents of ecologically risk cations (Cd2+, Pb2+) and anions (AsV as AsO43- and CrVI as CrO42-) from contaminated waters. The WBD indicated very good adsorption selectivity for Cd2+, Pb2+ and AsV at a high adsorption efficiency (˃90 %), and worse parameters for CrVI adsorption (˂30 % adsorption efficiency). The sorbent consumption was low (˂70 - 100 g per 1 g of contaminant) for cations (Cd2+, Pb2+) and more than four times higher for AsV. The adsorption of CrVI on WBD was ineffective. The adsorption of cations (Pb2+ and Cd2+) on CSW and anions (AsO43- and CrO42-) on CSWFe ran in the same manner as on WBD. Fe-modification of CSW to CSWFe increased its adsorption efficiency to anions by 15. - 20 %. The cations (Pb2+, Cd2+) were adsorbed almost quantitatively (≈100%) on the initial CSW at the sorbent consumption of 10 - 120 g per 1 g of contaminant. The adsorption of anions (AsV, CrVI) on CSWFe reached ˃95% for AsV and 40 - 60% for CrVI, at the sorbent consumption of 80 - 200 g per 1 g of contaminant.

Recent developments around nanotechnology that have been successfully brought to field applications have allowed its massification and generate an excellent projection towards its vast potential in different processes within the oil and gas industry. Particularly, The National University of Colombia - Medellín Headquarters, through the Surface Phenomena - Michael Polanyi Research Group and the Hydrocarbons Reservoirs Research Group, as well as Ecopetrol S.A. through their Technical management have planned to keep the country as a pioneer in nanotechnology-based developments at national and international level. Historically, nanoparticle and nanofluid base developments in the oil industry have been recorded since the beginning of the last decade. However, the first applications at the field level worldwide were developed in Colombia since 2011, mainly focused on IOR-type processes. Currently, the Industry-Academy-State triad has allowed diversifying the processes that are optimized by nanoparticles and nanofluids, including hydraulic fracturing, completion, drilling, production fluid treatment and improved recovery processes. The main objective of this work is to present the recent advances in applications at the laboratory and field level that have been developed in the aforementioned areas. Additionally, the projection and potential application of nanotechnology is presented in the three pillars of development of the country's oil industry that include EOR, unconventional deposits and offshore operations. It should be noted that, within this framework, the Colombian oil industry has been technically and scientifically strengthened through the training of personnel at the undergraduate, master's and doctoral levels, allowing the generation of new knowledge and new specialized programs on the subject. It is expected that from this work the appropriation of nanotechnology will be increased and the maintenance of Colombia as a pioneer in these types of developments.

In comparison with conventional chemical methods, plasma surface treatment offers several technological and economic advantages - method is less energetically demanding and requires no toxic or corrosive substances. In case of atmospheric pressure plasma processes there is no necessary to use any expensive vacuum equipment and surface treatment can be directly implemented to in-line manufacturing processes. In this study dielectric barrier discharge generated in ambient air above water-based electrode system was used to modify inner and/or outer surface of polyethylene tubes. Diffuse plasma layers generated along the treated polymeric surface modify surface properties (wettability, adhesion, …) to a depth of several nanometres while maintaining physical and chemical properties of bulk material. Treated samples were analysed by SEM-EDX, ATR-FTIR and static contact angle measurements. Results confirmed that plasma treatment led to significant improvement of surface wettability and indicated increased content of polar functional groups.
Acknowledgement: This research has been supported by the project LO1411(NPU I) funded by Ministry of Education, Youth and Sports of Czech Republic.

Ecological concern has recently resulted in a natural sources which are rich in cellulose, cheap and provide good prospective as reinforcements fillers in polymer matrix composites as recyclability and environmental safety. Rice husk is a cellulose-based fibrous material and a waste product of the rice processing industry. Biocomposites made from linear low density polyethylene (LLDPE) and rice husks (RH) in different content (10, 20, 30, 40, 50 wt. %) were prepared by melt compounded in laboratory Brabender mixer. The LLDPE/RH biocomposites were characterized by using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA). The effects of RH content on the thermal properties of the biocomposites have been discussed. The DSC results showed that the addition of the RH and increasing the RH content in biocomposites increased the crystallinity degree of the LLDPE/RH biocomposites at lower filler concentration of RH, i.e. 10 and 20 wt.% due to nucleating ability of RH . The results obtained by DMA analysis show a decrease of glass transition temperature (Tg) of LLDPE when it was blended with RH. In terms of thermal stability it has been found that the addition of RH decreased the thermal stability of the neat LLDPE.

Nanoscale zero-valent iron (NZVI) is one of the most important nanostructure for degradative remediation of environmental contaminants. In our research, NZVI was for the first time functionalized with cyclodextrins (CD), recently considered as excellent, environmentally friendly and cheap absorbents of toxic pollutants. Functionalization of the nano zero-valent iron by CD, their derivatives and polymers, can not only improve the ZVI nanoparticles stability and dispersibility, but also can complex toxic contaminants inside the CD cavities that will be further reduced by NZVI to a less toxic products. By this, one of the largest obstacles in the NZVI field i.e. lack of NZVI selectivity could be overcome. Moreover, reactivity towards a recalcitrant non-polar compound, that under standard conditions is not very reactive with the NZVI alone, has been shown herein.

In this paper, the gas sensitive structures based on porous silicon with incorporated nanoclusters of transition metals (Ni, W, Cu, Pd) to the molecules of butane and methane gases for different concentrations of methane in the range of concentrations of 30-500 ppm in air have been investigated. Firstly, porous silicon layers were formed by electrochemical etching of the p-type monocrystalline silicon substrate in a mixture of hydrofluoric acid and ethyl alcohol at a current density in an electrochemical cell in the range of 3 - 30 mA/cm2. Then, a thin metal films were deposited onto a porous silicon surface using the magnetron sputtering method with subsequent thermal treatment at a temperature of 450 - 650°С in an inert gas atmosphere (Ar) to fill pores with metal particles. Distribution of metal particles on a porous silicon matrix were analyzed using the secondary ion mass spectrometry. It was shown that metals are distributed throughout the thickness of porous silicon layer with a maximum concentration on the surface and minimal on the porous/monocrystalline silicon interface. The morphology of the porous silicon surface with incorporated particles of metals was characterized by scanning electron and atomic force microscopes. The gas sensitivity of the structures was investigated by the method of current-voltage curves. In our case, the kinetic dependences of the response signal (current) were taken with an applied voltage of 3.0 - 8V when exposed to adsorbed gas molecules and using air as the baseline gas. It was found the structures with copper/palladium composites into silicon pores show a high sensitivity to methane gas. Meanwhile, the structure with embedded particles of nickel are more sensitive to butane. Furthermore, the detailed mechanism of gas sensitivity of the sensor structures to flammable gases is discussed.

Recently, industrial development unavoidably generates large volumes of wastewater that contain emulsified oil/water mixtures. Preparing highly efficiently, cost-effective, and easy scale-up membranes for separation technology is challenging. Herein, various polymeric membranes based on electrospun nanofiber web. Polyamide 6 (PA6), polyvinylidene fluoride (PVDF) and polyacrylonitrile nanofibers were prepared needle-free electrospinning technique. Using heat-press, nanofiber webs were transferred on a substrate to create hybrid structure. Membrane surface morphology was investigated using a scanning electron microscope. The average pore size of the membranes was measured using custom-made porometer. The pore size of the PA6, PAN and PVDF membranes was found 0.64µ, 0.5 µ and 0.72µ, respectively. Oil-water mixture were prepared and membrane was immersed half in oil, half in water. The flux, selectivity and affinity of the membranes were compared. According to results, PA6 and PAN nanofibers showed hydrophilic/oleophobic performance and separated water from oil-water mixture. Contrary, PVDF membranes showed hydrophobic/oleophilic performance and separated oil from oil-water mixture. The flux of PA6, PAN and PVDF membranes flux was 5.84 L/(m2h), 4 L/(m2h), and 6.27 L/(m2h), respectively. It was found that the type of polymeric membranes had the biggest influence on the membrane selectivity for the oil-water mixture. The as-prepared membranes can be of great use in new separation technology and have great potential to deal with the separation of oil-water mixture in the near future due to their different selectivity, excellent physical/chemical resistance and mechanical properties.

The use of nZVI is well known method for remediation of groundwater contaminated with chlorinated hydrocarbons. The present paper investigates the ability of traditional nZVI and S-nZVI modified with sulphide ion (HS-) to reduce CHC in real wastewater sample. In the effort to enhance longevity and efficiency of the treatment, experiments were performed under applied voltage (patent 304152, owner MEGA a.s., TUL). Results showed elevated reactivity of nZVI in reactors with passing voltage. The decomposition of the CHC in DC supported reactors occurred several times faster than in reactors without added voltage. However, the analysis of products suggests different pathway of decomposition when S-nZVI is used. The main product of reductive dechlorination was acetylene as opposite to regular nZVI which produced predominantly ethene and ethane. The nZVI provided with DC showed the most rapid decline of all contaminants in the time frame of 5 days.

The water decontamination in terms of biofouling using electrolysis has been successfully demonstrated by many research groups. However, this cleaning process is still limited in industrial uses due to low chemical resistance of the employed materials (Ti, Ni, TiO2, etc.). From many developed cleaning procedures, an electrochemical oxidation is considered promising for the next generation water cleaning technology due to its versatility, mobility and no need for additional chemicals. Process performance mainly depends on both the electrode material and operating conditions. Here, boron doped diamond (BDD) is proposed as a very effective electrode material.
In this work, we present the utilization of BDD electrodes for the disinfection of drinking water contaminated by Escherichia coli. Bacteria in three different electrolytes (NaCl, phosphate buffer (PB) and phosphate buffer saline (PBS)) were electrolysed at current density of 10 mA/cm2 (0.7 W) for 2 hours at 25-30°C. After certain time intervals, water solutions were individually analysed by Raman and SEM measurements. Complementary, drop or spread plate cultivations were used for bacterial viability studies.
Electrolysed bacterial suspensions in PB showed relatively minor tenfold decrease of viability after 1 h, which is almost a comparable result with untreated control. On the other hand, experiments performed in NaCl and PBS resulted in a total elimination of all viable bacteria during first 10 minutes of electrolysis which indicate, that the bacterial elimination is determined to chlorine radicals (Cl•). Based on Raman and SEM, we propose time-dependent stages of bacterial death and disintegration in drinking water.

Cytostatic drugs are a broad group of chemotherapy compounds mainly applied for tumor, skin diseases and infections treatments. Anticancer pharmaceutics are exhibited carcinogenic, mutagenic and teratogenic activity and have been recognized as low biodegradable so their concentration would increase in the environment. Effective removal of pharmaceuticals in municipal wastewater treatment plants plays a critical role in preventing them from getting into the aquatic environment. Presented work focuses on the photocatalytic removal of poor biodegradable actual micropollutant - Imatinib (IMA) from aqueous solution. The 2.5 wt. % multi-walled carbon nanotubes (MWCNTs) modified TiO2 nanocomposite was synthesized by two methods: sol-gel (s-g) and hydrothermal (hyd). The anatase as a photocatalysts’ structure was confirmed by using X-day diffraction technique. Photoluminescence and UV-vis tests were used for investigation of photocatalysts optical properties. The scanning electron microscopy techniques used for morphology investigation showed the various location of MWCNTs in composites depending of synthesis method applied. Good photocatalytic properties of both 2.5% MWCNTs/TiO2 for imatinib degradation under UVA, and artificial solar light irradiation was showed. Imatinib was also removed and mineralized under visible light irradiation by 2.5% MWCNTs/TiO2(s-g). The study showed that MWCNTs contributed in increasing photocatalytic activity of TiO2 in solar and/or visible light due to retardation of electron-hole recombination and visible light absorption by modification of band-gap and/or sensitization.

Precleaning of float glass is an important step in manufacturing processes based on combining its surface with other materials. Cleanness, together with surface roughness and chemical activity affect adhesion properties of the substrate that are crucial for the quality of the final product. Atmospheric pressure plasma pretreatment was studied as a dry alternative to conventional wet cleaning methods of glass, with the aim at industrial requirements. Diffuse coplanar surface barrier discharge (DCSBD) and multi-hollow surface dielectric barrier discharge in air at atmospheric pressure were used on soda-lime glass to prove the applicability of thermally non-equilibrium plasma. Surface analyses by water contact angle measurement, X-ray photoelectron spectroscopy, atomic force microscopy and Fourier-transform infrared spectroscopy were complemented by industrial ball drop and bending tests realized on laminated safety glass. A highly effective and non-invasive surface treatment suitable for large-area processing was achieved with the plasma of DCSBD. Targeting the industrial applications, the DCSBD system was adjusted to the devices to enable contactless and in-line electrode implementation to the manufacturing processes. Thanks to the cooperation with a glass manufacturing company, these DCSBD operating devices proved advancement also under industrial conditions.

It’s well known that industries like textile, paper, cosmetics, rubber, plastics, food processing, are the important sources of dye pollution. Although the used techniques try to remove the dye from the wastewaters, small quantities remain after the discharge, making these conventional systems not effective for discoloration.
Adsorption using activate carbon (powdered or granular) is widely used for dye removal from wastewaters. However, it's very expensive because it need regeneration and reactive procedure. In this way our study is focused on characterisation, analysis and application of a nano activated carbon issued from the cryogenic grinding of olive stones.
The first part concerns the determination of the characteristics of nano activated carbons obtained from the olive stones, which were reduced to very small grounds by using a cryogenic grinding with liquid nitrogen. Chemical activation of this precursor at 450 °C was adopted by using the phosphoric acid as dehydration agent at 2/1 impregnation ratio. FTIR was carried out to identify the surface groups. The microscopic structure and surface were examined by a SEM/EDX and BET respectively. Results showed surface area and pore volume approaching 1000 m2/g and 1 cm3 respectively. The SEM imaging shows a Nanocrystalline structure and a highly developed porosity.
In the second part, we investigate the feasibility of adsorption of Methylene Blue on the Nano activated carbon prepared from olive stones. The stock solution was prepared by dissolving Methylene Blue in 1000 ml distilled water. The experiments were carried out at ambient temperature, with the initial concentration varying from 5-50 mg/l. The absorbance of dye solution was determined by a spectrophotometer at 665 nm wavelength. The amounts of dye adsorbed were calculated from the concentrations in solutions before and after adsorption.
Nano Activated Carbon issued from the cryogenic grinding of the olive stones seems to be a promising adsorbent for removal of the cationic dye Methylene Blue from water. Indeed, 5 g of adsorbent could almost completely decolorize solution of Methylene Blue (50 mg/l)

Agarose hydrogel was used as the transport medium for the investigation of the diffusion of lignohumate through plant cuticle. The cuticles were isolated from Prunus laurocerasus by two different methods: chemical and enzymatic. At first, the diffusion coefficient of lignohumate in agarose hydrogel was determined by means of the technique of diffusion couple: the donor part was enriched by lignohumate with homogeneous distribution on its whole volume and connected with the “pure” acceptor part without lignohumate. The diffusion coefficient was calculated on the basis of time development of diffusion flux through the interface. After that, the cuticle was placed into interface between donor and acceptor parts and the barrier ability of cuticles were characterized by the decrease in diffusion flux and the change of the concentration of lignohumate at the interface between donor and acceptor hydrogels. The transport through chemically and enzymatically cuticles as well as the abaxial (stomatous) and adaxial (astomatous) cuticles was investigated. Diffusion characteristics were determined, compared and discussed.

The disposal of used automotive tires is the source of many of worldwide environmental and economic problems. In fact, the non-degradability of these plastic materials leads to all kind of pollution which has several consequences on both the health and environment. A good solution from an economic and environmental standpoint is to reprocess the used tires into valuable products.
Activated carbons, which can be an alternative for the transformation of used tires, are materials composed mainly of carbon, and have a high adsorption capacity; this is due essentially to their large surface areas and to their highly developed nanoporous texture.
The present work is dedicated to the valorisation of the used tires by using cryogenic grinding with liquid nitrogen. The obtained nano-powder is used as raw material for developing adsorbents.
The first part of that study concerns the preparation of the tire powder by shredding a used tire into pieces of varying size. These pieces are emerged in liquid nitrogen at a temperature of -196 °C for 15min, and then grinded in a disc type grinder SODEM containing within its walls a certain volume of liquid nitrogen. Once crushed, the powder is sieved to different sizes followed by additional operations to clean it and separate if from all the impurities.
The obtained product obtained by the cryogenic method is compared with the one from the ambient method in order to show the advantages and the disadvantages.
The second part of this paper concerns the characterization of an activated carbon from the nano-powder, obtained from the cryogenic grinding of scrap tires, by using a chemical activation with phosphoric acid.

The physical and chemical properties as the structure, the morphology, the cristanality and the group surfaces characteristics of the obtained activated carbon were studied by using non-destructive characterization techniques. Fourier transform infrared (FTIR) study was carried out to identify the surface groups in the obtained activated carbon. The microscopic structure and surface were examined by a Scanning Electron Microscopy (SEM/EDX) and BET respectively.