SEKCE B - PRŮMYSLOVÉ A ENVIROMENTÁLNÍ APLIKACE NANOMATERIÁLŮ

Nanodiamonds (ND) are currently investigated for their valuable and combinable properties in the fields of quantum technologies, nanomedicine and energy. In addition, their semiconducting behavior inherited from bulk diamond, combined with the surface chemistry, brings photocatalytic assets. UV-illuminated hydrogenated nanodiamonds have been used as sources of solvated electrons for CO2 reduction [1]. Despite the bandgap (5.5 eV), several recent studies revealed a ND photoactivity in the visible range leading to H2 production comparable to TiO2 [2] or CO2 reduction [3].
After giving a state of art of ND photoactivity, the present lecture will focus on the complete and fast photodegradation of perfluorooctanoic acid (PFOA) to fluorine ions under solar-type illumination using highly crystalline hydrogenated milled nanodiamonds (H-MND). One pioneering study has been reported on the degradation of PFOS under deep UV light (254 nm) using hydrogenated detonation nanodiamonds as a source of solvated electrons [4]. While that study paves the way for the use of ND in PFAS degradation, several key aspects remain to be explored such as the influence of ND surface chemistry and crystalline quality, the associated underlying mechanisms and if solar-type illumination can be used instead of deep UV.
Under comparable conditions, H-MND outperforms conventional standalone photocatalysts, even in aerobic environments and under solar-type irradiation. These findings highlight the potential of H-MND to serve as an effective solution for PFAS remediation, whether used as a simple and reusable standalone photocatalyst or integrated into more advanced hybrid systems [5].
REFERENCES: [1] Zhang et al., Diam. Relat. Mater. 78 (2017) 24-30; [2] Marchal et al., Adv. Energy Sustain. Res. 5 (2024) 1-8; [3] Yoshikawa et al., Carbon N. Y. 218 (2024) 118689; [4] Maza et al., Appl. Catal. B Environ. 325 (2023) 122306; [5] Jimenez et al., doi.org/10.26434/chemrxiv-2025-zp563-v2

Cyclodextrin (CD) is a naturally occurring cyclic oligosaccharide molecule which has remarkable properties owing to the hydrophobic cavity of the CD, shown to bind a vast array of molecules including pharmaceuticals, pesticides, and more recently PFAS. PFAS, being per-/poly-fluoroalkyl substances are increasingly illustrated to be a troublesome pollutant due to their persistence, resistance, and toxicity. With remediation technologies currently inept for many of the PFAS present, CD and their derivatives have become the focus of much research as a strategy for capture of these problematic PFAS. Except for NMR titrations, which is exceptional for observing the site-specific interactions between PFAS-CD complexation, there has been no direct thermodynamic analysis of PFAS-CD complexation using calorimetry, also highly limited computational predictions for PFAS-CD binding. This work presents the first systematic DFT-level investigation of PFAS-CD binding, applying Grimme's CREST/CENSO multilevel strategy to the homologous series PF4 through PF8 with native β-CD, wherbey we achieve chemical accuracy (MAE = 0.71 kcal mol⁻¹) against experimental ITC measurements.
Findings show that electronic energies correlate nearly perfectly with experimental total free energies. Further, chain-length selectivity is governed primairly by electronic interactions—specifically van der Waals forces and electrostatics—with solvation and entropic corrections contributing an approximately constant offset. Notably, van der Waals interactions occur with anchoring by three carboxylate-to-primary-rim hydrogen bonds. Energy decomposition revealed that differential solvation penalties discriminate the binding affinity, which could explain why shorter chains, found to insert more deeply, bind more weakly because desolvation costs outweigh favorable geometry. This validated workflow could enabling computational screening of modified CDs and alternative PFAS structures for rational system design.

Carbon dots have emerged as attractive photoactive nanomaterials for artificial photosynthesis owing to their tunable optical properties, photostability, low toxicity, and scalable synthesis. Beyond their radiative behavior, they can also serve as multifunctional photocatalytic platforms capable of light harvesting, charge separation, electron storage, and redox catalysis. This presentation introduces a bioinspired carbon-dot system designed to mimic selected functional elements of cytochrome c oxidase. In this concept, triethanolamine acts as the sacrificial electron donor, the carbon-dot domain functions as an electron reservoir, and copper-containing porphyrin-like motifs serve as catalytic sites for oxygen reduction. Structural, optical, and light-induced EPR analyses are used to follow the key charge-transfer steps and connect them with hydrogen peroxide photoproduction, highlighting the potential of carbon dots for enzyme-inspired solar-to-chemical conversion.

Electrospun nanofiber membranes have gained increasing attention for water purification and desalination. The electrospinning process enables fabrication of membranes with high permeability and selectivity, tunable surface properties, tailored to specific contaminants. Polymers such as polyvinyliden fluorife (PVDF), polyimide (PI), polyethersulfone (PES), polyamide 6 (PA6), polyacrylonitrile (PAN) and biopolymers like cellulose acetate (CA) or chitosan can be selected or blended to optimize performance [1].
For industrial-scale production, needleless electrospinning, as developed by Elmarco, offers high-throughput manufacturing and facilitates commercial application. Moreover, Elmarco presents examples of already prepared nanofiber layers, which should be useful for liquid filtration. These samples, prepared from polymers mentioned above, could be used as starting point for optimization of these membranes for a specific field of liquid filtration.
Another key advantage of electrospun membranes is the ease of structural and surface modification. Hydrophilic or modified hydrophobic surfaces help reduce fouling and improve water flux. Post-treatment methods, such as plasma treatment or thermal annealing, enhance membrane stability and allow precise surface tuning [2]. Nanoparticle integration—using materials like TiO₂, silver or graphene oxide—further improves ion exchange, adsorption, antimicrobial action, and photocatalytic activity [3]. These combined strategies have demonstrated high desalination efficiency and long-term durability. Ongoing progress in green solvents, bio-based polymers, and scalable production supports future development. In conclusion, electrospinning offers a flexible and sustainable platform for developing advanced membranes to meet the demands of modern water treatment and desalination.
REFERENCES: [1] Ma, Z. et al. (2019). Surface modification of electrospun membranes for improved water treatment performance. Journal of Membrane Science, 580, 366-381; [2] Yin, J. et al. (2016). Nanomaterials in electrospun membranes for water treatment. Advanced Materials, 28(22), 4353-4367; [3] Liu, F. et al. (2020). Electrospun nanofiber membranes for advanced desalination and water purification. ACS Applied Materials & Interfaces, 12(45), 50072-50091.

Aqueous ammonium ion batteries (AAIBs) are an emerging sustainable energy technology owing to their high ionic conductivity, safety, low cost, and non-metallic charge carrier. 1,2 However, their practi-cal applicability is restricted by low energy density, a narrower potential window, and poor cycling sta-bility. 3,4
An entropy-engineered amino group-functionalized metal-organic framework (EnMOF-NH2) is reported as a promising cathode for high-performance AAIBs. EnMOF-NH2 consists of five metal nodes (Co, Ni, Fe, Mn, Mo) and an amino-functionalized benzene dicarboxylic acid linker (BDC-NH2), which pro-vides multiple redox centers, enhanced structural stability, and abundant hydrogen bonding sites for efficient NH4+ storage. The incorporation of Mo metal nodes into the multi-metallic MOF can strength-en the metal-ligand interaction and suppress the metal dissolution, while amino-functionalized BDC provides polarity to the framework and enables fast NH4+ storage through hydrogen bonding.
EnMOF-NH₂ achieves a high reversible capacity of 130.8 mAh g-¹ at 0.3 A g-¹ in 1.0 M (NH₄)₂SO₄, outperforming the non-amino-functionalized EnMOF-BDC. It exhibits excellent rate capability, and ca-pacity increases to 162% after 2500 cycles. A full cell coupled with an EnMOF-NH₂ cathode and perylene tetracarboxylic dianhydride (PTCDA) anode shows a wide voltage window of 0.01-1.8 V and retains 83% capacity over 1000 cycles.

Conventional supercapacitor electrodes rely on composites containing binders and conductive additives deposited on metallic current collectors, increasing electrochemically inactive mass and processing complexity. In this work, self-standing, binder-free electrodes were fabricated directly from cellulose fiber-based fabrics (regular structure, fiber diameter ~10 µm) and electrospun lignin-based fibers (random structure, fiber diameter ~2 µm). Their tailored fibrous structures also enable facile incorporation of heteroatoms during precursor preparation. Structural and chemical characterization was performed using XRD, BET, EDX, XPS, and SEM.
Hard carbons were prepared by tailored stabilization and carbonization. The final carbonization temperature was optimized to control interlayer spacing, electrical conductivity, and porosity. Stable hard carbon sheets exhibited interlayer spacing above 0.37 nm up to 1400 °C, suitable for Na-ion intercalation, while maintaining a low specific surface area (SBET as low as 22 m² g⁻¹). Activated carbons were produced by additional CO₂ activation. Activation temperature, time, and gas flow were optimized to obtain mechanically stable porous carbon sheets with surface areas up to 2200 m² g⁻¹.
Activated carbon electrodes delivered a specific capacitance of 196 F g⁻¹ and an energy density of 49.5 Wh kg⁻¹ in symmetric supercapacitor cells using an organic electrolyte. Hard carbon electrodes were evaluated in half-cells against metallic Na, and both materials were combined in an asymmetric HC/AC Na-ion capacitor. Initial devices demonstrated promising performance by combining the high energy density of batteries with the fast-charging capability of supercapacitors. These results demonstrate a viable, simplified, binder-free, and conductive carbon electrode architecture for supercapacitors, Na-ion batteries, and Na-ion capacitors.

Metal-organic frameworks (MOFs) have emerged as versatile functional materials for electrochemical energy storage owing to their high surface areas, tunable pore structures, compositional diversity, and well-defined metal-ligand coordination environments. These characteristics provide opportunities for engineering electrode materials with abundant electroactive sites and efficient ion transport. However, the intrinsically low electrical conductivity and, in some cases, limited structural stability of pristine MOFs remain important challenges for their direct application in supercapacitors and rechargeable batteries. The integration of MOFs with conductive and electrochemically active components to construct heterostructured architectures offers an effective strategy to overcome these limitations. The structure-property relationship in these materials is strongly governed by factors such as pore architecture, particle morphology, composition, heterointerface characteristics, and electronic structure. Rational interfacial engineering can therefore enhance specific capacitance or capacity, rate capability, cycling stability, and overall energy and power characteristics. Despite significant progress, challenges related to electrical conductivity, scalability, long-term stability, reproducibility, and understanding of interfacial charge-storage mechanisms. Continued development of precisely engineered MOF heterostructures is expected to provide new opportunities for the design of high-performance electrode materials for next-generation supercapacitors and rechargeable batteries.

Emerging polarization-driven phenomena are opening new opportunities for designing high-performance materials for sustainable energy conversion. Beyond conventional approaches based on electronic structure engineering and adsorption energetics, ferroic order, including ferroelectricity, ferromagnetism, and piezoelectricity, provides powerful means to regulate charge separation, carrier transport, and interfacial reaction kinetics. More recently, electron spin has emerged as an additional degree of freedom for controlling catalytic reactions, particularly the oxygen evolution reaction, where the spin-selective formation of triplet oxygen imposes an intrinsic kinetic limitation.
In this talk, I will present an overview of our ongoing and recent research on polarization engineering for solar energy conversion, with particular emphasis on ferroelectric, piezoelectric, and spin-polarized photoelectrocatalysis. First, I will discuss our work on nanocolumnar ferroelectric photoelectrodes and quantum dot-integrated piezoelectric systems, demonstrating how ferroic polarization can enhance charge separation and photoelectrochemical performance. I will then introduce our monolithically integrated multilayer photoanodes that exploit magnetically induced spin polarization to promote spin-selective charge transport during water oxidation. Finally, I will discuss how the convergence of ferroic order, spin engineering, and polarization-driven phenomena is establishing new paradigms for the design of next-generation electrochemical and photoelectrochemical systems, paving the way toward efficient and sustainable energy conversion technologies.

Electrode films are key functional components in hydrogen energy devices such as polymer electrolyte membrane fuel cells (PEMFCs) and water electrolyzers. Their nanoscale architecture, composed of catalyst particles, ionomer binders, and interconnected pores, enables efficient proton, electron, and gas transport, but also makes the electrodes susceptible to mechanical degradation under environmental stresses. Changes in temperature and humidity can induce swelling, shrinkage, and structural rearrangement of the ionomer phase, leading to deformation, cracking, and delamination. Under subzero conditions, freezing of confined water can generate additional internal stresses and further accelerate mechanical failure. This work investigates the mechanical reliability of ionomer-bound electrode films, with emphasis on nanostructural evolution under environmental stresses, intrinsic mechanical characterization using free-standing tensile testing, and strategies for improving mechanical robustness, including mitigation of freeze-induced damage. The findings provide insight into the relationship between nanoscale structure and macroscopic mechanical degradation and offer guidance for the design of more durable electrodes for hydrogen energy applications.

Exploiting pseudocapacitance in rationally engineered nanomaterials offers greater energy storage capacities at faster rates. The present research reports a high-performance Molybdenum Oxynitride (MoON) nanostructured material deposited directly over stainless-steel mesh (SSM) via the reactive magnetron sputtering technique for flexible symmetric supercapacitor (FSSC) application. The MoON/SSM flexible electrode manifests remarkable Na+-ion pseudocapacitive kinetics, delivering exceptional ~881.83 F.g-1 capacitance, thanks to the synergistically coupled interfaces and junctions between nanostructures of Mo2N, MoO2, and MoO3 co-existing phases, resulting in enhanced specific surface area, increased electroactive sites, improved ionic and electronic conductivity. Employing 3D Bode plots, b-value, and Dunn’s analysis, a comprehensive insight into the charge-storage mechanism has been presented, revealing the superiority of surface-controlled capacitive and pseudocapacitive kinetics. Utilizing PVA-Na2SO4 gel electrolyte, the assembled all-solid-state FSSC (MoON/SSM||MoON/SSM) exhibits impressive cell capacitance of 30.7 mF.cm-2 (438.59 F.g-1) at 0.125 mA.cm-2. Moreover, the FSSC device outputs superior energy density of 4.26 μWh.cm-2 (60.92 Wh.kg-1) and high power density of 2.5 mW.cm-2 (35.71 kW.kg-1). The device manifests remarkable flexibility and excellent electrochemical cyclability of ~91.94% over 10,000 continuous charge-discharge cycles. These intriguing pseudo-capacitive performances, combined with lightweight, cost-effective, industry-feasible, and environmentally sustainable attributes, make the present MoON-based FSSC a potential candidate for energy-storage applications in flexible electronics.

Platinum group metals such as Pt, Ru, Pd, Ir, etc., have superior performance for various catalytic applications. Due to their scarcity, efforts were being made to reduce or replace these noble metals. Atomic Layer Deposition (ALD) is one among the best technique to facilitate lowering of loading mass on a support of interest [1-6].
This presentation is focused on the growth of noble metal nanostructures - from single atoms, through atomic clusters up to nanoparticles - by Atomic Layer Deposition (ALD) on various substrates. They demonstrate an excellent electrocatalytic performance [1-3] for the hydrogen evolution reaction (HER).
Due to the governing surface energy variations between noble metals and support surfaces, the growth initiates as single atoms, continues through atomic clusters to nanoparticles (NP) and with a further increase in ALD cycles the agglomeration among NP’s dominates over the individual NP size increase, thus developing thin films of relatively higher thickness.
For electrocatalytic applications, it is important to choose the right substrates. Among the available ones, carbon papers (CP) and titania nanotube (TNT) layers are best choices considering their physio-chemical properties, availability, vast literature, and low costs incurred using these as support substrates in electrocatalysis and photocatalysis.
The presentation will introduce and describe the synthesis of Pt, Pd, Ru and Ir nanostructures - starting from single atoms, through NPs to solid films by ALD on CP substrates and TNT layers with high aspect ratios [2] and QCM crystals [3]. It will also include the corresponding physical and electrochemical characterization and encouraging results obtained in electrocatalysis.
REFERENCES: [1] B. Bawab et al., Chem. Eng. Journal 482 (2024) 148959; [2] C. Schott et al.. ACS Catalysis 15 (2025) 9035; [3] Thalluri, S.M., et al. Small. 19 (2023) 2300974; [4] Thalluri, S.M., , Energy Environmental Materials 8 (2025) e12864; [5] B. Bawab et al., Electrochim. Acta 429 (2022) 141044; [6] J. Rodriguez Pereira et al., Electrochimica Acta. 556 (2026) 148256.

The oxidative cleavage of alkynes represents a fundamental transformation for converting simple feedstock chemicals into synthetically valuable intermediates. However, the high bond dissociation energy of the carbon-carbon triple bond has posed significant challenges to achieving this transformation in a single, efficient step. In this study, we present an alternative strategy that enables the chemo selective oxidative cleavage of aromatic terminal alkynes under visible-light irradiation. This catalyst-free protocol proceeds under mild conditions, exhibits broad functional group tolerance, and offers a sustainable solution to a long-standing synthetic challenge. Using, lithium bromide and oxygen as the C-C bond activator, a catalyst free, organo-photochemical method for the chemo selective oxidation of aryl alkynes is devised. This process presents a wide spectrum of functional group sustainability and exhibits remarkable selectivity towards the cleavage of aromatic C-C triple bonds over comparable aliphatic scaffolds. In the presence of functional groups that are sensitive to oxidation, this method also permits the selectivity of aryl alkynes. The reaction procedure also supports excellent deuteration of aldehyde in situ when paired with a HAT reagent and deuterium oxide. The deuteration is highly selective to the aldehyde site alone in presence of other active sites as well, increasing the effectivity and selectivity of the reaction procedure.

Hydrogen-fueled proton exchange membrane fuel cells (PEMFCs) are a promising technology for transition to a climate-neutral economy. However, the cost and stability of oxygen reduction reaction (ORR) catalysts for PEMFCs cathode remain important issues, as the current platinum-based catalysts are expensive. Enhancing the stability of catalysts could potentially lower the overall cost by extending the operational lifetime of fuel cells.
One of the main mechanisms through which ORR catalyst degradation can manifest, alongside other paths including Ostwald ripening and particle detachment, is Pt dissolution. Preventing Pt dissolution is crucial to increase stability, as lost Pt atoms decrease active surface area and lead to decay of ORR catalyst activity.
In the present study, we investigated magnetron-sputtered Pt100-xRhx (x = 0, 6, 12 and 19) bimetallic alloys in conditions relevant for ORR catalysis. By controlling the alloy composition, the relationships between the composition, oxidation behavior and stability were studied. The alloys were characterized using a wide range of techniques, including scanning electron microscopy (SEM), scanning flow cell inductively coupled plasma mass spectrometry (SFC ICP-MS), energy-dispersive X-ray spectroscopy (EDX), synchrotron radiation X-ray photoelectron spectroscopy (SRPES), electrochemical X-ray photoelectron spectroscopy (EC-XPS), and cyclic voltammetry (CV).
We have examined the surface electronic structure and alloy formation using SRPES. SFC ICP-MS measurements have provided insight into the initial stages of dissolution of Pt and Rh in Pt-Rh alloys, connecting doping Pt with Rh with lower Pt dissolution. We used EC-XPS to explore the electronic structure and potential-dependent changes of oxidation states, and compared the findings with Pt-Rh dissolution dynamics investigated using SFC ICP-MS.

Finite fossil resources and fragile energy supply chains are driving the search for sustainable routes to fuels and chemicals. We report a functionalized graphene catalyst platform in which covalent grafting of amino acid and aminosulfonic acid groups tunes acidity and surface affinity, and delivers strong performance across several reactions relevant to a circular carbon economy. A taurine functionalized graphene solid acid catalyst converts glycerol to solketal under solvent free, room temperature conditions, with high activity, 7508 mmol g-1 h-1, and near quantitative selectivity, 99.9%.1 Theoretical analysis indicates that taurine plays a dual role, it increases Brønsted acidity and strengthens adsorption of polar reactants, which together explain the high rate and selectivity. Using the same design logic, an aminosulfonic acid functionalized graphene catalyst enables efficient biodiesel production. It shows high activity and selectivity for esterification of oleic acid to fatty acid methyl esters, and it converts common vegetable oils via transesterification. Two additional aminosulfonic acid variants show similar catalytic behavior, supporting the conclusion that paired amino and sulfonate functionalities are central to generating strong acidity.2 We also extend the approach to alcohol upgrading. An amino acid modified graphene scaffold stabilizes Rh at very low loadings and, after mild activation, forms cooperative metal ensembles that convert ethanol to n butanol at comparatively low temperature with good recyclability. In situ DRIFTS supports a bifunctional mechanism, atomically dispersed Rh sites dominate ethanol dehydrogenation, while nearby ultra small Rh aggregates promote subsequent C-C coupling and hydrogenation steps. Overall, functionalized graphene provides a practical route to recyclable catalysts that couple tunable acid chemistry with controlled metal speciation for glycerol valorization, biodiesel synthesis, and ethanol C-C coupling.
REFERENCES: [1] Cheruvathoor Poulose, A.; Medveď, M.; Bakuru, V. R.; Sharma, A.; Singh, D.; Kalidindi, S. B.; Bares, H.; Otyepka, M.; Jayaramulu, K.; Bakandritsos, A.; Zbořil, R., Acidic graphene organocatalyst for the superior transformation of wastes into high-added-value chemicals. Nat Commun 2023, 14 (1), 1373; [2] Cheruvathoor Poulose, A.; Bares, H.; Zaoralová, D.; Dědek, I.; Otyepka, M.; Bakandritsos, A.; Zbořil, R., Aminosulfonated Graphene as a Catalyst for Efficient Production of Biodiesel from Fatty Acids and Crude Vegetable Oils. Chemsuschem 2025, 18 (12), e202402488.

The efficacious use of CO2 as a sustainable C1 feedstock is still extremely challenging considering its kinetic inertness and thermodynamic stability. In this work, we report for the first time the design and development of a Zn-based single-atom catalyst (Zn SAC) anchored on a CeO2-SiO2 mesoporous support, which simultaneously enhance oxygen vacancy concentration, surface acidity and surface basicity. The extensive characterization results revealed that the incorporation of isolated Zn active sites into the Ce-SiO2 porous framework construct a synergistic catalytic environment, where oxygen vacancies facilitate CO₂ activation, while the balanced acidic and basic sites promote effective interaction with amine substrates (Figure 1). This tailored catalyst exhibits exceptional performance in the conversion of CO2 and various amines into value-added chemicals, including urea and carbamate derivatives. Notably, the reaction proceeds efficiently under relatively mild conditions, achieving high activity at a low CO₂ pressure of 1 MPa and lower reaction times compared to conventional systems [1-3]. The enhanced catalytic behavior is attributed to the atomically dispersed Zn centers, which maximize metal utilization efficiency and provide well-defined active sites for CO2 adsorption and activation. In contrast to previously reported catalytic systems that predominantly employ bulk metal catalysts often requiring high metal loadings and exhibiting lower turnover numbers (TON) the present Zn SAC system in heterostructure demonstrates superior catalytic efficiency, improved TON, and significantly reduced metal usage. The results imply the critical role of single-atom catalysis in tuning surface properties and advancing CO₂ valorization strategies. This study provides new insights into the rational design of multifunctional catalysts for sustainable chemical transformations involving CO2 in the field of academia as well as industry.

Carbon-carbon bond-forming reactions constitute one of the most fundamental transformations in organic synthesis, providing efficient access to highly functionalized molecules that serve as key intermediates in pharmaceuticals, natural products, and functional materials. Among these, the construction of C(sp)-C(sp) bonds through the homocoupling of terminal alkynes represents a straightforward and atom-economical strategy for the synthesis of valuable 1,3-diynes. However, these transformations are predominantly achieved using transition-metal catalysts, often requiring expensive metals, harsh reaction conditions, or stoichiometric oxidants, thereby limiting their sustainability and practical applicability.
Herein, we report a metal-free visible-light-mediated C(sp)-C(sp) homocoupling of phenylacetylenes enabled by a rationally designed donor-acceptor porous organic polymer (Pyr-PT) photocatalyst. The extended conjugated framework, incorporating electron-rich pyrene donor units and electron-deficient acceptor moieties, promotes efficient photoinduced charge separation under visible-light irradiation, generating long-lived charge carriers capable of driving the catalytic transformation without the need for any transition-metal cocatalyst.
Mechanistic investigations suggest that upon visible-light excitation, the Pyr-PT porous organic polymer undergoes effective electron transfer, while oxidation of sodium benzenesulfinate generates a reactive radical species that mediates hydrogen atom abstraction (HAT) from the terminal alkyne to produce a C(sp)-centered alkynyl radical. Subsequent radical coupling affords the corresponding 1,3-diynes with high efficiency. The porous architecture, visible-light absorption, and enhanced charge-transport properties of the polymer collectively contribute to its excellent photocatalytic performance.
This work provides a sustainable and environmentally benign strategy for C(sp)-C(sp) bond formation under mild conditions and demonstrates the potential of donor-acceptor porous organic polymers as efficient metal-free photocatalysts for challenging organic transformations.

Detonation nanodiamonds (DNDs) have attracted considerable interest for a wide range of applications, including quantum devices, sensors, lubricants, and diamond film growth. While significant progress has been achieved in the preparation and dispersion of DND colloids, the controlled deposition of DNDs onto solid substrates remains a key challenge for many solid-state applications.
In this presentation, two recently developed DND deposition techniques are introduced. The first technique enables nanometer-scale ordered arrangement of DNDs on substrate surfaces. By combining electron-beam lithography with local surface functionalization, surface charge polarity is selectively controlled, allowing electrostatic deposition of DNDs into line-and-space and dot-array patterns with feature sizes down to several tens of nanometers. The second technique is an electrostatic layer-by-layer deposition process employing DND colloids with opposite zeta potentials. Alternating immersion in positively and negatively charged DND suspensions enables homogeneous buildup of multilayer DND coatings.
Applications of these techniques are also presented. The ordered arrangement method has been applied to patterned growth of nanocrystalline diamond films, offering a potential bottom-up route for fabrication of diamond-based micro/nanoelectromechanical devices. The layer-by-layer deposition method has been used to fabricate diamond photocatalytic electrodes for visible-light-driven CO₂ reduction. The results demonstrate that DND layer thickness strongly influences the photoelectrochemical performance and reduction activity. These findings highlight new opportunities for integrating DNDs into advanced electronic, photonic, and energy-conversion devices.

Carbon nanotubes (CNTs), due to the lack of edge sites, remain structurally stable at extremely high current densities up to tens of kA/cm2. This makes them a good candidate for the construction of high performance electrodes, at which oxygen evolution reaction occurs (OER) [1]. Another reaction in which CNTs may be considered is hydroxyl radical generation (HRG) used to mineralization of organic pollutants. The one-electron pathway of HRG with standard potential of +1.8 V vs. SHE competes with the more favored four-electron pathway of OER, whose standard potential is +1.23 V vs. SHE. In this study, we show that nanodiamonds (NDs) permanently adsorb on CNTs in liquid phase that results in creation of stable ND@CNT hybrids. Direct electron transfer between NDs and CNTs is manifested itself through a shift of the Raman G and 2D bands in CNTs. ND@CNT electrodes show slower kinetics of OER than pristine CNT electrodes. On the other hand, the efficiency of *OH generation probed by methylene blue degradation is higher on ND@CNT anodes. The effect of suppressing the OER and enhancing *OH generation efficiency is easily tuned by adjusting the nanodiamond content in the hybrid system. In this way, we demonstrate that the electrocatalytic properties of hybrid systems composed of sp2- and sp3-bonded nanocarbons can be controlled.
REFERENCES: [1] P. Szroeder et al. Molecules 30 (2025) 1265.
ACKNOWLEDGEMENTS: The research was funded by the Ministry of Science and Higher Education under the program ‘Regional Initiative of Excellence’ in years 2024-2027, Project No. RID/SP/0048/2024/01.

One-dimensional nanostructured materials have attracted considerable attention owing to their high surface area and unique functional properties. [1-2]. Among the available fabrication techniques, centrifugal spinning has emerged as a scalable and cost-effective method for producing polymeric and inorganic fibers [3-5]. Centrifugal spinning is a simple, scalable fiber fabrication technique that uses centrifugal force to produce continuous fibers and is less sensitive to environmental conditions than conventional methods [6].
In this work, a novel approach for the synthesis of zinc oxide (ZnO) fibers is presented that is based on centrifugal spinning from optimized spinning solutions, followed by tailored annealing. To the best of our knowledge, this is the first study demonstrating the synthesis of ZnO fibers via centrifugal spinning using a polymeric precursor.
The antibacterial properties [7] and vulcanization performance [8] of the resulting ZnO fibers were evaluated and compared with those of commercial ZnO nanoparticles (NPs). Initially, precursor fibers were produced by centrifugal spinning using polyvinylpyrrolidone (PVP) and zinc nitrate solutions. The precursor fibers were annealed at 500°C and subsequently milled to an average length of 6.6 µm. Morphological, structural, and surface characterization was performed using SEM, XRD, and BET, followed by antibacterial and vulcanization testing. The ZnO fibers exhibited superior antibacterial activity and enhanced vulcanization performance compared with commercial ZnO nanoparticles. These findings demonstrate that ZnO fibers represent a promising and more sustainable alternative to conventional ZnO nanoparticles, enabling reduced ZnO loading in rubber vulcanization without compromising performance while offering enhanced antibacterial functionality.
REFERENCES: [1] S.K. Satpathy, et al., Mater. Today Commun. 28 (2021) 102725; [2] A. Machín, et al., Materials 14 (2021) 2609; [3] P.K. Chennam, et al., J. Mater. Res. Technol. 28 (2024) 2199-2205; [4] N.N. Joda, et al., J. Ind. Text. 54 (2024); [5] N.N. Joda, et al., Appl. Surf. Sci. 686 (2025) 162132; [6] J. Ahmed, et al., Nanobiotechnol. 16 (2024) e1916; [7] N.N. Joda, et al., RSC Advances, in review; [8] N.N. Joda, et al., Polymer testing, in review.

Graphitic carbon nitride (g-C₃N₄) has emerged as a promising metal-free photocatalyst for solar-driven environmental remediation; however, its practical application is hindered by rapid charge-carrier recombination and inefficient oxidant activation. Herein, we demonstrated a simple molecular precursor-assisted thermal reconstruction strategy to tailor the electronic structure of melamine-derived g-C₃N₄ using choline chloride. The treatment transforms bulk g-C₃N₄ into exfoliated 2D nanosheets with an enlarged specific surface area and reconstructed electronic structure. Spectroscopic analyses reveal suppressed photoluminescence quantum yield together with enhanced non-radiative charge-transfer pathways, indicating more efficient separation and utilization of photogenerated charge carriers. The engineered 2D g-C₃N₄ exhibits remarkable photocatalytic activation of peroxymonosulfate (PMS) under visible-light, enabling broad range of organic micropollutants degradation. The catalyst maintains high activity over a wide range of pollutant concentrations, across a broad pH window, and in different water matrices, achieving complete degradation of contaminants within 10 min under optimized conditions. The enhanced performance is attributed to molecular precursor-induced electronic reconstruction, which promotes efficient interfacial charge transfer and photo-induced PMS activation without the need for metal cocatalysts. In sum, the findings provide facile design principles for defect-engineered graphitic materials with improved photoelectronic functionality for environmental applications.

Proton exchange membrane fuel cells (PEMFCs) offer clean energy conversion and high power density. However, their wider use is limited by the high cost of platinum and the dependence of conventional catalyst layers on PFSA-based ionomer. In this work, spark ablation was used to produce platinum nanoparticles and deposit them directly on the gas diffusion layers (GDLs). The resulting catalyst layers were ionomer-free and contained no PFSA. The catalytic activity of platinum nanoparticles synthesized under different hydrogen concentrations in the carrier gas and the effects of total platinum loading in the catalyst layers were evaluated in PEMFC single-cell studies with an active area of 5 cm2.
Adding hydrogen to the carrier gas improved the Pt utilization and increased the power density. Catalyst layers prepared with up to 5% H2 performed better than those deposited without H2 in carrier gas. This improvement can be linked to reduced Pt oxidation during the nanoparticle formation and deposition. Additionally, increasing H2 concentration to 7% did not further improve PEMFC performance, suggesting that a higher concentration may adversely affect the stability or the nanostructure of the Pt catalyst. Increasing Pt loading improved the maximum power density, but the performance is not proportional to the additional Pt. Based on the single-cell results, catalyst layers were deposited with 5% H2 and tested in a three-cell PEMFC stack with an active area of 25 cm2, demonstrating their suitability beyond single cells. These results show the potential of hydrogen-assisted spark ablation to produce high-purity Pt nanoparticles and ionomer- and PFSA-free catalyst layers for PEMFC applications.