Sulfur vacancy-rich ZnIn2S4 nanosheet arrays for visible-light-driven water splitting

In this study, ZnIn2S4 nanosheet arrays (NSAs) were synthesized on transparent conductive F doped SnO2 (FTO) substrates via a facile hydrothermal method. S vacancies were introduced on the ZnIn2S4 surface by a H-2-Ar plasma treatment. The sulfur vacancies were identified clearly by electron paramagnetic resonance (EPR). Under different plasma powers, the S vacancies concentration can be adjusted. With increasing the plasma power, both the photocurrent and H-2 evolution rate of ZnIn2S4 were increased. Through a 60 W plasma treatment, ZnIn2S4 displayed a photocurrent density of 0.3 mAcm(-2) at 0.3 VRHE, which was roughly 2 times higher than that of untreated ZnIn2S4. Correspondingly, the H-2 evolution rate was 2.74 mu mol cm(-2 )h(-1) for ZnIn2S4 NSA, in contrast to that of 0.96 mu mol cm(-2) h(-1) for pristine ZnIn2S4 NSA. The enhanced PEC performance was attributed to the enhancements of both the visible light absorption and carrier separation. Moreover, the S vacancies also acted as traps to retard the electron-hole recombination. This work provides a novel strategy for enhancing its PEC hydrogen evolution.

Automated summary

In this study, ZnIn2S4 nanosheet arrays (NSAs) were synthesized and sulfur vacancies were introduced on the surface through plasma treatment. The enhanced photoelectrochemical (PEC) performance of ZnIn2S4, including increased photocurrent and H-2 evolution rate, was attributed to improved visible light absorption and carrier separation, as well as the trapping effect of the sulfur vacancies. This work presents a novel strategy for enhancing the PEC hydrogen evolution of ZnIn2S4.