Oxygen Electrocatalysis at MnIII-O x-C Hybrid Heterojunction: An Electronic Synergy or Cooperative Catalysis?

Abstract

The interface at the metal oxide−carbon hybrid heterojunction is the source to the well-known “synergistic effect” in catalysis. Understanding the structure−function properties is key for designing more advanced catalyst− support systems. Using a model MnIII−Ox single-layer catalyst on carbon, we herein report a full elucidation to the catalytic synergism at the hybrid heterojunction in the oxygen reduction reaction (ORR). The successful fabrication of the single-layer catalyst from bottom-up is fully characterized by the X-ray absorption fine structure and high-resolution transmission electron microscopy. For oxygen electrocatalysis over this model hybrid heterostructure, our results, from both theory and experiment, show that the synergistic ORR truly undergoes a cooperated two-step electrocatalysis with catalytic promotion (ΔEonset = 60 mV) near the heterojunction and over the single-layer catalyst through an interfacial electronic interplay, rather than an abstruse transition towards a one-step dissociative pathway. Finally, we report a superior peroxide-reducing activity of 432.5 mA cm−2 mg(M)−1 over the MnIII−Ox single-layer. Show more