Hydrogen evolution from MoSe₀/WO₃(001) heterojunction by photocatalytic water splitting: A density functional theory study

Photocatalytic water splitting for hydrogen evaluation as a green approach for energy production has received extensive attention from researchers. The strongly reducing single layer MoSe2 and oxidizing WO3(0 0 1) were constructed as a MoSe2/WO3(0 0 1) heterojunction (MWH). The electronic structure and optical properties of the MWH were calculated and analyzed using the density functional theory (DFT) to reveal the internal causes of the photogenerated carrier migration path and the photocatalytic mechanism. The electronic structure and optical absorption analysis showed that MoSe2 and WO3 contributed to the valence band maximum (VBM) and conduction band minimum (CBM) of MWH, respectively, narrowing the bandgap and broadening the optical absorption range. The energy band bending results indicated that the MWH was a Z-scheme photocatalytic heterojunction. Through the segregation of the oxidation (WO3) and reduction sites (MoSe2), photogenerated electrons and holes could be separated, and the formation of a built-in electric field inhibited the recombination of photogenerated carriers. Given that the MWH exhibited superior oxidation (3.302 eV) and reduction (-0.128 eV) properties, it has great potential for applications in the field of photocatalytic hydrogen production.