Modulating the Electronic Structure of Metal Halide Perovskites for Efficient Selective CO2 Photoreduction to CO

Abstract

Metal halide perovskites (MHPs) have recently held great promise for solar-to-fuel conversion via artificial photosynthesis technology. However, the conversion efficiency of most MHP photocatalysts is still far below that necessary for their practical implementation. Modulating the electronic structure is a promising strategy to solve this issue. Here, taking Cs2AgBiBr6 as a prototype, we investigate the interplay between the local electronic structure of Cs2AgBiBr6 and its photocatalytic performance via introducing heteroatoms. Theoretical calculations reveal that Au heteroatom-mediated orbital rehybridization induces high electron densities and tailors the d-band center of Cs2AgBiBr6, endowing more upshifted d-band center and enhanced adsorption strength of intermediates, thereby resulting in decreased energy barriers for selective CO2 photoreduction to CO product. Experimentally, we report the Cu-incorporated Cs2AgBiBr6 catalyst for selective photoreduction of CO2 to CO in a solid-gas system without sacrificial agents, yielding an on average CO generation rate of 47.3 μmol g−1 with approximately 100% selectively, outperforming the pure Cs2AgBiBr6 and comparable to the reported MHP-based photocatalysts. This work showcases modulating the electronic structure of MHP photocatalysts offering a powerful route for effective solar fuel generation.