WS2/MoSe2 van der Waals heterojunctions applied to photocatalysts for overall water splitting

Addressing the energy crisis and environmental pollution necessitates efficient photocatalysts for hydrogen production via water hydrolysis. This study uncovers the potential of a novel photocatalyst - two-dimensional transition metal dichalcogenides (TMDs) heterojunction. Using density functional theory (DFT), we examined the photocatalytic performance of the two-dimensional WS2/MoSe2 heterojunctions for water splitting. Our findings reveal a direct band gap of 1.65 eV and a type II band structure in the heterojunction. This structure facilitates the separation of electrons and holes in the WS2 and MoSe2 monolayers, thereby significantly inhibiting electron-hole recombination. Furthermore, high optical absorption coefficient (105 cm - 1), small effective mass of electron(hole), low interlayer barrier, and adjustable band-edge stress in the heterostructure collectively enhance photocatalytic efficiency.