Strong precious metal–metal oxide interaction for oxygen reduction reaction: A strategy for efficient catalyst design

Oxygen reduction reaction (ORR) is an electrochemical reaction in which dissolved oxygen in an electrolyte is reduced to OH-/H2O when receiving electrons. This reaction plays a crucial role in shaping the efficiency of both metal-air batteries and fuel cells, and precious metals are the dominant catalysts carrying out the ORR in their cathodes. However, how to manipulate the electronic structure of precious metals as active sites to further promote ORR performance and maximize the utilization rate is still under development. Metal oxide serves as suitable and promising support that can strongly interact with precious metals for both activity and durability enhancement. Herein, we present recent research updates on strong precious metal-metal oxide interaction (SPMMOI) utilized in ORR. We start by introducing the background of ORR, the issues to be solved, and its practical applications followed by a thorough discussion of the reaction mechanism and comprehensive evaluation protocols of performance. We then provide a complete understanding of the working principle of SPMMOI and highlight the related advances. Finally, we summarize the merits of the precious metal-metal oxide system and propose the research direction as well as some urgent problems to be addressed in the future.