Structural steering of bismuth chalcogenides to oriented bismuth catalysts for efficient CO2 reduction

Abstract

The electrochemical structural reconstruction of precatalysts opens up a promising avenue for the emergence of highly active phases in the carbon dioxide reduction reaction. However, steering this dynamic process toward specific crystalline facets remains a significant challenge. Herein, we demonstrate a precursor-mediated structural steering strategy using bismuth chalcogenide nanosheets as precatalysts. Despite similar macroscopic morphologies, the intrinsic lattice memory of the precatalyst dictates divergent reconstruction pathways. The layered rhombohedral Bi₂Se₃ template facilitates the formation of highly {00l}-oriented metallic Bi nanograins, while the orthorhombic ribbon-like Bi₂S₃ yields randomized polycrystalline Bi. Coaxial transmission Kikuchi diffraction, along with in situ spectroscopy, confirms that the {00l}-textured Bi(Se) surface stabilizes Bi with a unique, ordered lattice oxygen coordination environment. Mechanistic studies reveal that Bi coordinating with lattice O sites on the {00l} facets effectively suppresses the competitive hydrogen evolution while lowering the energetics for *OCHO formation, thereby achieving a peak faradaic efficiency of 95% for formate production. Shifting from the view of reconstruction as a chaotic event, this strategy provides a predictable relationship between precatalysts and their active states, which can be extended to the rational design of other metallic catalyst systems.