General synthesis and atomic arrangement identification of ordered Bi–Pd intermetallics with tunable electrocatalytic CO2 reduction selectivity

Abstract

Intermetallic compounds (IMCs) with fixed chemical composition and ordered crystallographic arrangement are highly desirable platforms for elucidating the precise correlation between structures and performances in catalysis. However, diffusing a metal atom into a lattice of another metal to form a controllably regular metal occupancy remains a huge challenge. Herein, we develop a general and tractable solvothermal method to synthesize the Bi-Pd IMCs family, including Bi₂Pd, BiPd, Bi₃Pd₅, Bi₂Pd₅, Bi₃Pd₈ and BiPd₃. By employing electrocatalytic CO₂ reduction as a model reaction, we deeply elucidated the interplay between Bi-Pd IMCs and key intermediates. Specific surface atomic arrangements endow Bi-Pd IMCs different relative surface binding affinities and adsorption configuration for *OCHO, *COOH and *H intermediate, thus exhibiting substantially selective generation of formate (Bi₂Pd), CO (BiPd₃) and H₂ (Bi₂Pd₅). This work provides a comprehensive understanding of the specific structure-performance correlation of IMCs, which serves as a valuable paradigm for precisely modulating catalyst material structures.

Precise synthesis of Intermetallic compounds and understanding of the structure-performance correlation are highly desirable in catalysis. Here, the authors develop a general method to synthesize up to six BiPd intermetallic compounds and study the mechanism toward the electrocatalytic carbon dioxide reduction reaction.