Construction of a multi-interfacial-electron transfer scheme for efficient CO2 photoreduction: a case study using CdIn2S4 micro-flower spheres modified with Au nanoparticles and reduced graphene oxide

Abstract

CdIn₂S₄ micro-flower spheres modified with Au NPs and rGO have been designed for CO₂ photoreduction. The photoproduction yields of CO and CH₄ were 4 and 5 times higher than that of pure CdIn₂S₄, respectively. The photoproduction of CO and CH₄ from the photocatalytic CO₂ reduction process has been evidenced by ¹³C isotope tracer tests. Au NPs act as both the acceptor of photogenerated electrons and the donor of hot electrons at the CdIn₂S₄ and rGO interface. Three electron transfer channels: CdIn₂S₄ → Au → rGO, CdIn₂S₄ → Au, and Au → rGO, efficiently improve the transfer efficiency of electrons. Meanwhile, CO₂ adsorption is largely improved, as confirmed by DFT calculations which indicate that the CO₂ adsorption ability of the C sites from rGO has been enhanced by Au NPs. In situ FTIR has been carried out to research the CO₂ photoreduction process. This work demonstrates the importance of efficient electron transfer and excellent CO₂ adsorption in improving the efficiency of CO₂ photoreduction, providing an inspiring concept for future advancement in this area.