PtCo-based nanocatalyst for oxygen reduction reaction: Recent highlights on synthesis strategy and catalytic mechanism

Oxygen reduction reaction over Pt-based catalyst is one of the most significant cathode reactions in fuel cells. However, low reserves and high price of Pt have motivated researchers worldwide seeking enhanced utilization efficiency and durability by doping non-noble metals to form Pt-based alloy catalysts. Alloying Pt with Co has been recognized as one of the most effective approaches to achieve this goal. PtCo bimetal combination is one of the most promising candidates to synthesize highly efficient catalysts for oxygen reduction reaction (ORR) applications, owing to its relatively more suitable oxygen binding energy for four-electron transfer reactions. Recently, impressive strategies have been developed to fabricate more active and stable PtCo-based multimetallic alloys with tailorable size and morphology. This paper aims to summarize the most recent highlights on the study of the relationship between preparation strategies, morphologies, electroactivities of the PtCo-based catalyst at atomic level and further the relevant reaction mechanism. The challenges and opportunities on the further development of electrocatalysts for fuel cells are included to provide reference for the practical application.