Enhanced Solar Fuel Production over In ₂O ₃@Co ₂VO ₄ Hierarchical Nanofibers with S‐Scheme Charge Separation Mechanism

Abstract

The conversion of CO ₂ into valuable solar fuels via photocatalysis is a promising strategy for addressing energy shortages and environmental crises. Here, novel In ₂O ₃@Co ₂VO ₄ hierarchical heterostructures are fabricated by in situ growing Co ₂VO ₄ nanorods onto In ₂O ₃ nanofibers. First‐principle calculations and X‐ray photoelectron spectroscopy (XPS) measurements reveal the electron transfer between In ₂O ₃ and Co ₂VO ₄ driven by the difference in work functions, thus creating an interfacial electric field and bending the bands at the interfaces. In this case, the photogenerated electrons in In ₂O ₃ transport to Co ₂VO ₄ and recombine with its holes, indicating the formation of In ₂O ₃@Co ₂VO ₄ S‐scheme heterojunctions and resulting in effective separation of charge carriers, as confirmed by in situ irradiation XPS. The unique S‐scheme mechanism, along with the enhanced optical absorption and the lower Gibbs free energy change for the production of ^*CHO, significantly contributes to the efficient CO ₂ photoreduction into CO and CH ₄ in the absence of any molecule cocatalyst or scavenger. Density functional theory simulation and in situ diffuse reflectance infrared Fourier transform spectroscopy are employed to elucidate the reaction mechanism in detail.