Enhanced Oxygen Reduction Reaction Activity Due to Electronic Effects between Ag and Mn₃O₄ in Alkaline Media

Ag is considered to be among the most promising electrocatalysts for the oxygen reduction reaction (ORR) in alkaline media and is suitable for application in various electrochemical energy devices such as metal–air batteries and alkaline fuel cells. In this study, we studied the role of the electronic effects induced by strong metal support interactions in Ag/Mn₃O₄/C in enhancing the ORR activity in alkaline media. Ag supported on Mn₃O₄ showed a much higher ORR activity than Ag supported on carbon, and an upshift in the d-band center was observed in the former case, due to charge transfer from Ag to Mn. Further, the strain effect observed by X-ray absorption fine structure analysis, induced an increase in the O–O bond split kinetics due to upshift of the d-band center, resulting in enhanced ORR activity on Ag/Mn₃O₄/C. In conclusion, we propose that in-depth consideration of electronic effects is essential when designing metal/metal oxide catalysts for the ORR in alkaline media.