Interfacial electron interactions governed photoactivity and selectivity evolution of carbon dioxide photoreduction with spinel cobalt oxide based hollow hetero-nanocubes

Abstract

In this work, an efficient CO₂ photoreduction catalyst based on Co₃O₄/ZnIn₂S₄ hollow hetero-nanocubes is precisely constructed via an in-situ transformation of cobalt-organic framework followed by a solvothermal reaction. Comprehensive in-situ spectroscopic analyses and theoretical calculations have revealed that the critical interfacial electron interactions (IEIs) effects on both photoactivity evolution and selectivity modulation in the Co₃O₄/ZnIn₂S₄ hetero-structure. As the content of ZnIn₂S₄ increases in the hetero-structure, the photoactivity exhibits a volcano-like evolution profile but the CH₄ selectivity reduces monotonously. The improved photoactivity is attributed to the IEIs-promoted charge separation as well as the specific-surface-area effect in terms of electron unitization rate, and the electronic structure of Co₃O₄ is tuned and the energy barrier for the key reaction intermediate *CHO is reduced, leading to improved CH₄ selection in comparison with bare Co₃O₄. The IEIs-mediated production selectivity is further verified by a Co₃O₄/CeO₂ heterojunction, indicating a certain universality of the IEI effect.