In situ fabrication of a plasmonic Bi@Bi2O2CO3 core–shell heterostructure for photocatalytic CO2 reduction: structural insights into selectivity modulation

Abstract

The precise design of active sites and light absorbers is essential for developing highly efficient photocatalysts for CO₂ reduction. Core–shell heterostructures constructed based on large-sized plasmonic Bi metals are ideal candidates because of the utilization of full-spectrum light and effective charge separation. However, the mechanism of selectivity modulation of large-sized Bi@semiconductor photocatalysts has yet to be explored in depth. Herein, a plasmonic Bi@Bi₂O₂CO₃ core–shell heterostructure was successfully synthesized via a facile solvothermal treatment in deep eutectic solvents, demonstrating highly efficient photocatalytic CO₂ reduction. This structure features a sizeable Bi sphere with a thin, epitaxially grown Bi₂O₂CO₃ shell, which allows for the utilization of the entire light spectrum. Additionally, the oxygen vacancies in the Bi₂O₂CO₃ shell can rapidly trap electrons transferred from the Bi core via Bi–O–Bi bonds, thereby forming abundant electron-rich interfaces that serve as the active sites for activating reactant molecules and facilitating the reaction.