Development of new high-entropy oxide catalysts by the anodic oxidation of high-entropy alloys

ended

High-entropy oxides (HEOs) are a new category of materials constituted of five or more elements that are randomly distributed in a single phase. Such materials can have better properties than conventional oxides, related to the lattice distortion and synergistic effects of the component. Due to this lattice distortion and the uneven electron-cloud distribution between the metals and the oxygen, HEOs can impact on different catalytic reactions, such as CO2 reduction, H2S removal and the degradation of pollutants. However, HEO testing and application in catalysis is an undeveloped field. The conventional photocatalysts, such as TiO2, are mainly used in slurry conditions (demanding a post-filtration step) and present a low quantum efficiency and low activity under visible light. Doping or co-doping of conventional catalysts can promote changes in the crystalline structure and improve the photocatalytic activity. Thus, the use of new, multi-element materials such as HEOs appears to be an excellent, innovative alternative to overcome these drawbacks. HEOs can be synthesised by the anodic oxidation of high-entropy alloys (HEAs), creating strongly attached nanostructures that do not need a filtration step, and with enhanced photocatalysts properties. Using this strategy, our ambition is to develop a new and highly efficient photocatalyst, which will contribute to a major step forward in catalysis. The produced materials will be fully characterised and the photocatalytic efficiency will be evaluated over the degradation of new pollutants present in water such as pharmaceuticals, pesticides, hormones, microplastics, etc. and compared with conventional/commercial photocatalysts.