Novel Approach of Diffusion‐Controlled Sequential Reduction to Synthesize Dual‐Atomic‐Site Alloy for Enhanced Bifunctional Electrocatalysis in Acidic and Alkaline Media

Abstract

AbstractThe tailoring of active sites is closely related to the substrate. Dual‐atom catalysts (DACs) have been achieved on doped carbon, oxides, and 2D materials, but are rarely reported on metals, due to the challenges of sintering and alloying using metal as the host. Herein, an innovative approach to anchor isolated single atoms as dual‐atomic‐site alloy (DASA) through two‐step pyrolysis of porous structure is proposed. Firstly, the role of Zn and Co in generating pores during the pyrolysis of zeolite imidazolate framework (ZIFs) is revealed, and a hierarchical porous structure with self‐supported Co particles is achieved by the first‐step pyrolysis. Diffusion‐controlled reduction of precursors containing target metals is then allowed through hierarchical structures by second‐step pyrolysis, so to address the challenge of sintering and alloying at pyrolysis of high temperatures. The approach is demonstrated by synthesizing Ir1Ni1@Co/N‐C DASA, with outstanding bifunctional oxygen reduction/evolution reaction (ORR/OER) performance in both acidic and alkaline media, which is rarely reported. The density functional theory (DFT) calculations represent that adsorption‐free energies of intermediates OH and O are regulated to nearly 0 eV by Ir1 and Ni1 on Co. This work demonstrates a new path of constructing DASA using the designed porous structure, inspiring catalysts design in a related field.