The search for renewable and clean energy sources is a key aspect for sustainable development as energy consumption has continuously increased over the years concomitantly with environmental concerns caused by the use of fossil fuels. Semiconductor materials have great potential for acting as photocatalysts for solar fuel production, a potential energy source able to solve both energy and environmental concerns. Among the studied semiconductor materials, those based on niobium pentacation are still shallowly explored, although the number of publications and patents on Nb(V)-based photocatalysts has increased in the last years. A large variety of Nb(V)-based materials exhibit suitable electronic/morphological properties for light-driving reactions. Not only the extensive group of Nb₂O₅ polymorphs is explored, but also many types of layered niobates, mixed oxides, and Nb(V)-doped semiconductors. Therefore, the aim of this manuscript is to provide a review of the latest developments of niobium based photocatalysts for energy conversion into fuels, more specifically, CO₂ reduction to hydrocarbons or H₂ evolution from water. Additionally, the main strategies for improving the photocatalytic performance of niobium-based materials are discussed.

The interaction of light with semiconducting materials becomes the center of a wide range of technologies, such as photocatalysis. This technology has recently attracted increasing attention due to its prospective uses in green energy and environmental remediation. The characterization of the electronic structure of the semiconductors is essential to a deep understanding of the photocatalytic process since they influence and govern the photocatalytic activity by the formation of reactive radical species. Electron paramagnetic resonance (EPR) spectroscopy is a unique analytical tool that can be employed to monitor the photoinduced phenomena occurring in the solid and liquid phases and provides precise insights into the dynamic and reactivity of the photocatalyst under different experimental conditions. This review focus on the application of EPR in the observation of paramagnetic centers formed upon irradiation of titanium dioxide and niobium oxide photocatalysts. TiO₂ and Nb₂O₅ are very well-known semiconductors that have been widely used for photocatalytic applications. A large number of experimental results on both materials offer a reliable platform to illustrate the contribution of the EPR studies on heterogeneous photocatalysis, particularly in monitoring the photogenerated charge carriers, trap states, and surface charge transfer steps. A detailed overview of EPR-spin trapping techniques in mechanistic studies to follow the nature of the photogenerated species in suspension during the photocatalytic process is presented. The role of the electron donors or the electron acceptors and their effect on the photocatalytic process in the solid or the liquid phase are highlighted.

This review article highlights the advantages of niobium as a dopant and a coating constituent for improving cycling performance of layered Ni-rich oxide cathodes in liquid- and solid-electrolyte-based Li-ion batteries.

Superionic sulfide solid electrolytes (SEs) are of considerable interest for application in solid‐state batteries, but suffer from limited stability. When in combination with state‐of‐the‐art cathode active materials (CAMs), severe degradation at the CAM/SE interface occurs during electrochemical cycling. To improve upon the interfacial stability, inert coatings can be applied to the CAM particles, with the goal of preventing direct contact to the SE. In this study, different methods of depositing coatings, including hexagonal boron nitride, tungsten sulfide and exfoliated ((CH₃(CH₂)₃)₄N)₄Nb₆O₁₇, in the form of nanosheets onto the free surface of a Ni‐rich LiNi_xCo_yMn_zO₂ (NCM) CAM are examined and compared with one another. While dry coating is shown to produce relatively uniform coatings (good surface coverage), the secondary particle morphology of the NCM makes ball milling as a mechanical deposition method less attractive. In contrast, deposition from dispersions in organic solvents yields protective coatings with a lower degree of surface coverage. The different materials are electrochemically tested in liquid‐ and solid‐electrolyte‐based lithium‐ion batteries. A stabilizing effect from nanosheet coating is only observed for the cells with lithium thiophosphate SE.

Lithium nickel oxide (LNO) is a promising cathode candidate in various next‐generation battery technologies. To increase its stability, doping and surface coating have become key strategies. Among various elements, niobium stands out for its dual role as an effective dopant and the advantages of its oxide phases as coatings. In this study, we explore Nb‐based coating of LNO, utilizing methods that minimize or eliminate solvent use. Additionally, the coated samples were treated at two different temperatures to study their effect on properties and electrochemical performance. Our results demonstrate that the coating process strongly affects the cell cyclability and further highlight the potential of Nb‐based protective coatings in enhancing LNO as a cathode active material for application in high‐energy‐density Li‐ion batteries.