LAUSR

Abstract Photocatalytic water splitting using semiconductor electrocatalysts in photoelectrochemical cells is an appealing approach to converting sunlight and water into clean and renewable hydrogen fuel. Janus MoSSe monolayer has recently been suggested as a promising photocatalyst for water splitting. Here we report a theoretical first-principles analysis on the feasibility of this material to be a photocatalyst for water-splitting. The results show that H2 can be easily produced by the photo-reduction reaction of 2H2O + 2e- → p h o t o n H2 + 2OH– on the Se-surface, whereas it is difficult to produce O2 by the photo-oxidation reaction of 2H2O + 4 h+ → p h o t o n O2 + 4H+ on the S-surface. We conclude that the Janus MoSSe monolayer is an inefficient catalyst for photocatalytic overall water-splitting.