Oxygen vacancies and interfaces enhancing photocatalytic hydrogen production in mesoporous CNT/TiO2 hybrids

We demonstrate a unique route towards hierarchical assemblies of mesoporous TiO2 and CNT/TiO2 photocatalysts by a combination of electrospinning and sol\u2013gel methods. The resulting materials exhibit a mesoporous network of highly crystalline, well-connected inorganic nanocrystals with an order of magnitude higher photocatalytic activity than individualised TiO2 nanoparticles. The in-situ combination of small amounts of MWCNTs with TiO2 to form an electrospun CNT/TiO2 hybrid further enhanced the oxide photoactivity considerably, reaching hydrogen evolution rates of 1218 \u3bcmol/h in water splitting in the presence of sacrificial reagents under UV irradiation. We also discuss the effect of oxygen vacancies on the oxide crystallisation and phase transformation. These vacancies lead to inter-bandgap states and a lower flat band potential that facilitates the photocatalytic process

Дослідження методичного забезпечення матеріального стимулювання діяльності з інноваційно-технологічного розвитку

The article defines the nature of income, expenses and profit from the activities of enterprises for innovation and technological development; feasibility of establishing the net profit within their fund, out of which consumer share is to be used as bonus payments for employees. It is suggested to use the graph theory for providing the efficiency of innovation and technological activities in manufacturing enterprise. Methodological provision is grounded for calculating bonus payments for employees of enterprises ensuring innovation and technological developmentУ дослідженні визначено: сутність доходів, витрат та прибутку від діяльності з інноваційно-технологічного розвитку підприємств; доцільність створення у складі чистого прибутку їх фонду, з якого споживчу частину використовувати для преміювання працівників. Запропоновано використання теорії графів для встановлення ефективності інноваційно-технологічної діяльності промислового підприємства. Обґрунтовано методичне забезпечення розрахунку преміальних виплат працівникам підприємств, що забезпечують інноваційно-технологічний розвито

Problems of floating vulnerabilities in ensuring mobile application security

The article is focused on the development of a method for detecting and eliminating floating vulnerabilities in mobile applications, their nature is described, and existing methods of detecting and neutralizing floating vulnerabilities are investigated, their defects are noted. The developed method is based on analyzing the state of the application at different points in time and comparing it with a reference state. The proposed algorithm includes fixing the initial state, discrete analysis, detection and identification of vulnerabilities, their elimination, and prevention of additional risks. The scope of application of the results includes the developing and securing of mobile applications for Android operating system. The conclusions of the paper confirm the importance of detecting and preventing floating vulnerabilities to ensure a high level of information protection. The developed method allows to effectively detect and eliminate vulnerabilities, which contributes to the creation of secure and protected applications for users of mobile devices

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

Polyoxometalates (POMs) are molecular metal oxide clusters that feature a broad range of structures and functionalities, making them one of the most versatile classes of inorganic molecular materials. They have attracted widespread attention in homogeneous catalysis. Due to the challenges associated with their aggregation, precipitation, and degradation under operational conditions and to extend their scope of applications, various strategies of depositing POMs on heterogeneous substrates have been developed. Recent ground-breaking developments in the materials chemistry of supported POM composites are summarized and links between molecular-level understanding of POM-support interactions and macroscopic effects including new or optimized reactivities, improved stability, and novel function are established. Current limitations and future challenges in studying these complex composite materials are highlighted, and cutting-edge experimental and theoretical methods that will lead to an improved understanding of synergisms between POM and support material from the molecular through to the nano- and micrometer level are discussed. Future development in this fast-moving field is explored and emerging fields of research in POM heterogenization are identified

Elucidation of a Core–Shell Structure in Phenyl-Grafted Carbon Nitride/TiO2 Nanohybrids for Visible-Light-Mediated H2 Production with Simultaneous Rhodamine B Degradation

Dual-functional photocatalysts help to maximize resource utilization in water remediation, but often they are visiblelight- inactive, toxic, and cost-intensive. Herein, a type-II heterojunction visible-light-active photocatalyst is reported for tandem degradation of Rhodamine B and generation of H2. A Rhodamine B degradation rate of 2.3 × 10−2 min−1 and H2 production activity of 5789 μmol h−1 g−1 are shown. The hybrid shows a gradient core− shell morphology with a visible - light-absorbing phenyl-modified carbon nitride (PhCN) core and a porous PhCN/TiO2 outer shell, resulting in an enhanced interaction between the catalyst and the surroundings. The nanoscale crystallization of TiO2 on PhCN’s surface, shifts the triazine network structure, while autoclave treatments further increase the band gap and suppress charge carrier recombination. The influence of nanoscale morphological changes on photocatalytic activity was examined by varying the component ratios and thermal treatments, highlighting the strong correlation between the nanoscale architecture and the enhanced catalytic activity. This work provides a detailed guide to the exploration of environmentally friendly dual-functional photocatalysts

Ordered Mesoporous TiO2 Gyroids: Effects of Pore Architecture and Nb-Doping on Photocatalytic Hydrogen Evolution under UV and Visible Irradiation

Pure and Nb-doped TiO2 photocatalysts with highly ordered alternating gyroid architecture and well-controllable mesopore size of 15 nm via co-assembly of a poly(isoprene)-block-poly(styrene)-block-poly(ethylene oxide) block copolymer are synthesized. A combined effort by electron microscopy, X-ray scattering, photoluminescence, X-ray photoelectron spectroscopy, Raman spectroscopy, and density functional theory simulations reveals that the addition of small amounts of Nb results in the substitution of Ti4+ with isolated Nb5+ species that introduces inter-bandgap states, while at high concentrations, Nb prefers to cluster forming shallow trap states within the conduction band minimum of TiO2. The gyroidal photocatalysts are remarkably active toward hydrogen evolution under UV and visible light due to the open 3D network, where large mesopores ensure efficient pore diffusion and high photon harvesting. The gyroids yield unprecedented high evolution rates beyond 1000 µmol h−1 (per 10 mg catalyst), outperforming even the benchmark P25-TiO2 more than fivefold. Under UV light, the Nb-doping reduces the activity due to the introduction of charge recombination centers, while the activity in the visible triple upon incorporation is owed to a more efficient absorption due to inter-bandgap states. This unique pore architecture may further offer hitherto undiscovered optical benefits to photocatalysis, related to chiral and metamaterial-like behavior, which will stimulate further studies focusing on novel light–matter interactions

2D-2D PhCN/WS2 exfoliated nanosheets for visible-light hydrogen production: A platinum-free Co-catalyst approach

Substituting fossil fuels with green energy sources such as H2 is one of the prime objectives of achieving a sustainable and carbon-neutral future. In this work, a noble-metal-free 2D-2D hybrid photocatalyst PhCN/WS2 is reported for application in hydrogen production under visible-light irradiation, where WS2 is utilized as an environmentally friendly co-catalyst. The synthesis and characterization of 2D Phenyl-modified carbon nitride (PhCN) and 2D WS2 via liquid-phase exfoliation are systematically investigated. The effectiveness of a solventmediated self-assembly is highlighted, and the effect of WS2 flake size on the photocatalytic activity of the hybrid is examined. The hybridization of exfoliated PhCN with two-dimensional (2D) WS2 demonstrates a 42-fold enhancement in hydrogen evolution compared to exfoliated PhCN alone under visible light. This improvement is attributed to the role of WS2 as an effective hydrogen evolution reaction (HER) co-catalyst. The utilization of larger WS2 nanoflakes proved to be ideal to establish fast charge carrier transportation networks