Band-Edge Electronic Structure on Photo(electro)catalytic Performance of ABO₂ (A = Cu, Ag; B = Al, Ga, In): Elucidating the Role of Valence Electron States

A profound understanding of the band-edge electronic structure is crucial for advancing the development of highly efficient photocatalytic materials and unraveling the underlying mechanisms. This study employs a unified and consistent assessment protocol, offering a systematic exploration of the inherent connections between the band-edge electronic structure and the photo(electro)catalytic performance of a series of delafossite ABO2 compounds (A = Cu, Ag; B = Al, Ga, In). These compounds exhibit characteristics of indirect bandgap semiconductors, with fundamental and optical bandgaps spanning from 1.45 to 3.57 eV. Notably, the Cu-based ABO2 compounds display a significantly larger fundamental bandgap and excel as photocathode materials when the B-site element is held constant. Among these, CuInO2 emerges as the most promising candidate, showcasing superior photo(electro)catalytic performance. Extensive density functional theory calculations unravel intricate insights into the interplay between the band-edge electronic structure and valence orbital hybridization of the A- and B-site elements, providing invaluable perspectives for comprehending and enhancing the photo(electro)catalytic performance of such compounds. The findings in this study not only establish robust theoretical foundations for integrating ABO2 compounds into the field of photo(electro)catalysis but also lay the groundwork for future material design and optimization.