Synergistic effect of sulfur vacancy, internal electric field and Mo-S bond toward highly-efficient charge utilization for MoS2/Sv-MnS/ZnIn2S4 photocatalysts

Abstract

ZnIn₂S₄ is a promising and typical semiconductor for photocatalytic water splitting into hydrogen production. However, the low charge-carrier utilization restricts its hydrogen evolution performance and practical application. In this work, a synergistic strategy of sulfur vacancy (S_v), internal electric field (IEF) and Mo-S bond was utilized for improving the charge-carrier utilization of MoS₂/S_v-MnS/ZnIn₂S₄ composites. In particular, Z-scheme S_v-MnS/ZnIn₂S₄ heterojunction not only tackled the charge-carrier recombination problem but also improved the redox capability. Meanwhile, Schottky-type MoS₂/S_v-MnS contact further promoted the charge transfer through Mo-S bond “bridge”, accelerated the surface hydrogen reduction reaction kinetics, and thus boosted the charge-carrier utilization. As a result, the optimal MoS₂/S_v-MnS/ZnIn₂S₄ catalysts could expeditiously produce 1.75 mL of hydrogen production within 3 h, and achieve a photocatalytic hydrogen evolution rate of 13.02 mmol g^-1 h^-1. This work provides an ingenious method to synthesize ZnIn₂S₄-based photocatalysts with highly-efficient charge-carrier utilization.