Atomic‐Level Regulation of Cu‐Based Electrocatalyst for Enhancing Oxygen Reduction Reaction: From Single Atoms to Polymetallic Active Sites

Abstract The slow kinetics of cathodic oxygen reduction reactions (ORR) in fuel cells and the high cost of commercial Pt‐based catalysts limit their large‐scale application. Cu‐based single‐atom catalysts (SACs) have received increasing attention as a promising ORR catalyst due to their high atom utilization, high thermodynamic activity, adjustable electronic structure, and low cost. Herein, the recent research progress of Cu‐based catalysts is reviewed from single atom to polymetallic active sites for ORR. First, the design and synthesis method of Cu‐based SACs are summarized. Then the atomic‐level structure regulation strategy of Cu‐based catalyst is proposed to improve the ORR performance. The different ORR catalytic mechanism based on the different Cu active sites is further revealed. Finally, the design principle of high‐performance Cu‐based SACs is proposed for ORR and the opportunities and challenges are further prospected.