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

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.