Escalating the synergism on CdZnS via Ag2S/Cu2S co-catalysts: Boosts hydrogen evolution from water splitting under sunlight

Abstract

Photocatalytic hydrogen production through water splitting is one of the effective ways to fulfill future energy demands. In current study, Ag and Cu were simultaneously incorporated into CdZnS through hydrothermal reaction to synthesize 1 % Ag2S/Cu2S codoped-CdZnS. The catalysts were characterized via XRD, FT-IR, SEM, EDX, UV–Vis/DRS, XPS, BET, PL and EIS techniques. It has been observed that 1 % Ag2S/Cu2S is optimized amount of dopants that enables CdZnS to produce hydrogen with 9.76 mmol g−1h−1 rate. This amount of H2 is 3 times higher than that of bare CdZnS (2.91 mmol g−1h−1). Photocatalytic activity shown by 1 % Ag2S/Cu2S-CdZnS is due the incorporation of Ag and Cu which exist in the form of Ag2S and Cu2S clusters respectively and causes synergistic effect during photoreaction. During the photoreactions, oxidation half reactions occur at Ag2S, while reduction half reaction at Cu2S (i.e. conversion of H+ ions to H2). On the basis of the results, it can be concluded that Cu2S acts as reduction co-catalyst while Ag2S serves as oxidation co-catalyst in water reduction reaction. This work could offer efficient and low cost photocatalysts for hydrogen production from the water splitting reactions.