Novel CoMn2O4-ZnIn2S4 hollow heterostructure cage for efficient photocatalytic hydrogen evolution

Semiconductor photocatalytic hydrogen evolution (PHE) is used to convert solar energy to hydrogen energy. Therefore, a low-cost, effective, and dependable photocatalyst could be a viable solution to environmental and energy crises. However, performing energy-conversion reactions by preparing photocatalysts with suitable photoabsorption and effective charge separation is challenging. Herein, a novel CoMn2O4-ZnIn2S4 (CMO-ZIS) hollow microcube composite catalyst with a p-n heterojunction is constructed, in which ZnIn2S4 nanosheets are grown in situ on the surfaces of CoMn2O4 hollow microcubes. Surprisingly, 10% CoMn2O4-ZnIn2S4 (CMO-ZIS-10) exhibits a PHE rate of up to 11.04 mmol h-1 g-1, which is approximately 3.6 times higher than that of pure ZnIn2S4. In addition, to maintain the excellent visible light absorption efficiency of ZnIn2S4 nanosheets, the closecontact heterogeneous interface of CMO-ZIS enables easy separation and transfer of the carriers. Furthermore, the hollow structure increases the absorption efficiency of sunlight and provides more active sites, thus increasing the reactivity of photocatalyst. In this paper, we report a workable approach for building heterojunction photocatalysts powered by water splitting.