Decorating CsPbBr3 with In2O3 seeds to build intimate direct Z-scheme heterojunction for promoted photocatalytic CO2 reduction

Abstract

Building heterojunctions has proven its efficiency in promoting charge separation for highly efficient photocatalysis. However, most heterojunctions often suffer from inadequate interfacial contact between the two semiconductor phases, hindering charge separation and producing suboptimal photocatalytic performance. Herein, leveraging the soft lattice feature of halide perovskite, we intentionally introduced In₂O₃ nanoparticles as seeds in situ during the crystallization process of CsPbBr₃, constructing In₂O₃/CsPbBr₃ heterojunction with intimate and abundant interface contact. Through in situ X-ray photoelectron spectroscopy and band structure analysis, we revealed the creation of a direct Z-type heterojunction that combines the catalytic advantages of both CsPbBr₃ and In₂O₃ for CO₂ reduction and water oxidation, respectively. The enhanced interfacial contact further enables this heterojunction to separate more photogenerated charges and prolong carrier lifetime effectively. Benefiting from the improved charge utilization, as well as the chemisorption and activation of CO₂ molecules on the catalyst, the In₂O₃/CsPbBr₃ heterojunction exhibits significantly enhanced performance in CO₂ photoreduction, achieving a 3.8-fold increase in the photoelectron consumption rate as compared to that of CsPbBr₃ alone. This study emphasizes the critical importance of a tight and rich heterojunction interface in achieving efficient photocatalytic reactions.