Unraveling the photocatalytic potential of transition metal sulfide and selenide monolayers for overall water splitting and photo-corrosion inhibition

Photocatalytic water splitting is a promising route to alleviate energy crises and provide clean renewable energy. However, finding the right materials for photocatalytic water splitting is challenging owing to its multilevel complexity. Herein, transition metal sulfide and selenide (TMSS) monolayers were screened to find the best possible monolayers for overall water splitting. Properties such as suitable band edges, oxidation and reduction potential, catalytic activities and solar to hydrogen (STH) efficiency were considered. Among various TMSS monolayers, MoS2, WS2, PtSe2, PdSe2, and NiSe2 have suitable conduction and valence band edges to trigger the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) simultaneously in acidic media. Moreover, the MoS2, PtSe2, PdSe2 and NiSe2 monolayers can effectively resist oxidative and reductive photo-corrosion in acidic and WS2 monolayers in neutral environments during water splitting. All monolayers have robust catalytic activities in the predicted electrolytes with HER overpotential near zero, and OERs are 0.53, 1.01 and 0.99 V for PtSe2, PdSe2 and NiSe2 monolayers, respectively. The STH efficiencies were also found to be high for MoS2 (10.4%), PtSe2 (22.2%), PdSe2 (19.6%), NiSe2 (20.1%) in acidic medium and WS2 (11.1%) in neutral medium. The predicted monolayers show promise for practical application as bifunctional photocatalysts in acidic and neutral environments. A systematic study was carried out to identify transition metal sulfide and selenide (TMSS) monolayers, which resist both photo-degradation and photo-corrosion in a single electrolyte towards overall water splitting (OWS).