Photocatalytic overall water splitting (POWS) is a developing method of green hydrogen production that utilises light as an energy source. Lanthanide tantalum perovskite oxynitrides (LnTaON2, Ln = lanthanide) are promising photocatalyst candidates as their valence and conduction band positions are suitable for POWS and their small bandgaps (1.8-2.4 eV) allow for utilisation of visible light. For lanthanides other than lanthanum, LnTaON2 perovskites remain underexplored for photocatalytic water splitting, with little work undertaken to optimise their photocatalytic activity and efficiency. In contrast, many successful synthetic variations have been explored to improve the photocatalytic activity of LaTaON2, including solid solution formation, morphology control and heterojunction formation. An overview of current work into non-lanthanum LnTaON2 photocatalysts is provided, along with the successful strategies utilised to improve the photocatalytic performance of LaTaON2, providing a toolbox of techniques to apply to non-lanthanum LnTaON2 photocatalysts to improve their photocatalytic performance in the future.
Bio-greases offer a more sustainable alternative to synthetic-based greases, mitigating ecological harm while ensuring effective lubrication in environmentally sensitive applications. This study examines the formulation and performance of bio-greases derived from renewable resources, such as vegetable oils and biogenic thickeners. It underscores their advantages over conventional petroleum-based lubricants, particularly in terms of biodegradability and non-toxicity. A novel blend of cashew nut shell oil (CNSO), combined with fumed silica (FS) as a thickener and zinc dialkyl dithiophosphate (ZDDP) as an additive, was investigated to enhance wear resistance, biodegradability and other lubricating properties. This study highlights the significance of thickener consistency in converting liquid base oils into semi-solid greases, which is essential for effective lubrication. Various assessments, including extreme pressure (EP) and tribological analyses, demonstrate that the bio-grease samples exhibit non-Newtonian shear-thinning behaviour, with performance metrics suggesting potential applications in food processing and agriculture. The results indicate that the addition of additives such as ZDDP can considerably enhance the lubricating properties and decrease the coefficient of friction (COF) in bio-greases.
