Research progress in alloy catalysts for oxygen reduction reaction

In the realm of new energy batteries, metal-air batteries and fuel cells exhibit promising prospects for broad market applications due to their high energy density, cost-effective manufacturing processes, and negligible atmospheric pollution. The oxygen reduction reaction (ORR) serves as a crucial cathode reaction in these battery systems. However, its relatively sluggish kinetics hinders the widespread adoption of such batteries. Therefore, efficient oxygen reduction catalysts are required to enhance the rate of ORR. Although traditional platinum (Pt) catalyst exhibits good electrocatalytic performance for ORR, it is difficult to be widely used because of its high cost and limited availability of resources. Alloy catalysts are anticipated to serve as substitutes for Pt catalysts by effectively enhancing catalytic activity while reducing production costs. Currently reported alloy catalysts in literature primarily augment their oxygen reduction activity through carbon carriers, heterojunction effects, amorphous structures or metal-organic framework-derived structures with heteroatom-doped composite alloys. This paper provides a comprehensive review on the research progress pertaining to Pt-based alloy catalysts, Pd-based alloy catalysts, and Fe-based alloy catalysts while summarizing the advantages and challenges associated with existing alloy catalyst systems.