A density functional theory study of thermally activated water splitting on the CuWO4 (010) surface

CuWO4 shows promise as a suitable material for solar-driven water splitting to aid progress towards sustainable and carbon-free energy generation. In this work, we report a computational study of catalytic water splitting and hydrogen generation at CuWO4 surfaces, employing calculations based on the density functional theory with on-site Coulomb and long-range dispersion corrections (DFT+U-D3). We have analyzed three potential thermodynamic and kinetic reaction profiles at the pristine CuWO4 surface and one potential profile at the reduced CuWO4 surface, examining the structural and electronic properties of the intermediates, as well as the transition states along the different pathways. Our findings reveal that along the pathway on the reduced surface, oxygen vacancies introduced in the surface led to under-coordinated Cu and W atoms and localized excess electrons, which significantly enhance the hydrogen evolution reaction.