Oxygen evolution reaction at the Mo/W-doped bismuth vanadate surface: Assessing the dopant role by DFT calculations

The first-principles investigation of M-doped BiVO4-based materials (M = Mo, W) provides a comprehensive understanding of the dopant role in enhancing the photocatalytic properties for Oxygen Evolution Reaction (OER), which is the key-process for water splitting. We found that the beneficial effect of Mo/W doping on bismuth vanadate stems from structural surface re-organizations with the formation of a peculiar site (Biopp), which stabilizes both hydration and catalytic capabilities. Water adsorption is more favourable on Biopp site rather than on top of the dopant Mo/W atoms. Also, the catalytic performances for OER are significantly improved at Biopp site thanks to a stabilization of the crucial intermediate along the OER mechanism. Therefore, the Mo/W dopants exert a non-innocent indirect effect on the catalysis by activating the under-coordinated Biopp site via a long-range pull-back mechanism. These findings pave the route to new design strategies based on doping and defect engineering to push further the development of new photocatalysts for water splitting.