In-N-In Sites Boosting Interfacial Charge Transfer in Carbon-Coated Hollow Tubular In2O3/ZnIn2S4 Heterostructure Derived from In-MOF for Enhanced Photocatalytic Hydrogen Evolution

A hierarchical hollow tubular In2O3/ZnIn2S4 heterostructure was rationally designed by growing thin-layered ZnIn2S4 on the surface of carbon-coated hollow tubular In2O3 (C/HT-In2O3) that was derived from In-MOF as a photocatalyst for the photocatalytic hydrogen evolution (PHE) reaction. The fast interfacial charge transfer and significantly enhanced PHE activity could be ascribed to the narrowed band gap of C/HT-In2O3 and the inclined formation of the staggered heterostructure between C/HT-In2O3 and ZnIn2S4. The former was caused by the coordinated In-N-In sites as revealed by EXAFS analysis, while the latter was proved by density functional theory (DFT) calculation. Additionally, the high electronic conduction of carbon for bridging charge separation from C/HT-In2O3 to ZnIn2S4 further accelerated the protonation process. It was found that the optimum H-2 evolution rate reached 920.5 mu mol/m(2) when the mass proportion of counterparts was set at 1:2, about 13.2 and 6.6 times higher than that of pristine C/HT-In2O3 and ZnIn2S4, respectively. This work demonstrated the feasibility of establishing coordinated In-N-In sites in the interface of the carbon-coated HT-In2O3/ZnIn2S4 heterostructure for boosting charge transfer and introduced an ideal light-activated catalyst for PHE reactions from water.

Automated summary

A hierarchical hollow tubular In2O3/ZnIn2S4 heterostructure was designed by growing thin-layered ZnIn2S4 on the surface of carbon-coated hollow tubular In2O3, which showed significantly enhanced photocatalytic hydrogen evolution activity. The enhanced activity was attributed to narrowed band gap of C/HT-In2O3 and formation of staggered heterostructure between C/HT-In2O3 and ZnIn2S4, which facilitated fast interfacial charge transfer.