Janus PtSSe: A promising cocatalyst of g-C3N4 for solar water splitting with improved light absorption and efficient carrier separation

Stacking diverse two-dimensional (2D) materials to construct heterostructures is considered to be a promising way for designing efficient photocatalyst. In this study, we proposed g-CN/PtSSe heterostructure and examined its potential as photocatalysts by investigating its geometric, electronic, and optical properties through first-principles calculation. The results show that the g-CN/PtSSe presents type-II band arrangement and establishes an internal electric field from g-CN to PtSSe, which facilitates the movement of photogenerated carriers via the Z-scheme path. This interaction effectively suppresses the recombination of charge carriers. The changes of Gibbs free energy in hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) indicate that the g-CN/PtSSe heterostructure can promote spontaneous reactions of photocatalytic water splitting. Notably, the g-CN/PtSSe heterostructures demonstrate a higher light absorption efficiency to their corresponding monolayer structures. These findings demonstrate that g-CN/PtSSe heterostructure has significant potential as a viable photocatalyst for water splitting in the foreseeable future.