First-Principles Calculations of 2D Janus WSSiN2Monolayer for Photocatalytic Water Splitting

Hunting for high-performance photocatalysts to achieve efficient solar conversion is still far from ideal goals. Here, a kind of Janus structure, ASSiN2 (A = Cr, Mo, W) monolayers, is first proposed to explore their photocatalytic activity using the first-principles calculations. It is found that the Janus ASSiN2 monolayers are structurally stable and exhibit semiconductor behaviors with indirect bandgaps of 1.47, 2.86, and 3.02 eV, respectively. According to the comprehensive analysis of charge density difference, it is confirmed that an enhanced intrinsic electric field exists in the Janus structures, which could facilitate the separation of photogenerated carriers. Noteworthily, only the band-edge potentials of the WSSiN2 monolayer fully satisfy the redox conditions of photocatalytic water splitting. Meanwhile, the high electron mobility up to 1098.36 cm2·V–1·s–1 and strong visible-light absorption ability can be obtained in the WSSiN2 monolayer, indicating its great application potential in photocatalysis. The findings will offer reliable evidence for further developing 2D Janus materials as high-performance photocatalysts.