Wu, Kuang-HsuHuang, XingTahini, H. A.Kappen, PeterHuang, RuiTan, XinJang, L.-Y.Ding, YuxiaoSmith, SeanQi, WeiGentle, Ian RossSu, Dang-ShengAmal, RoseWang, Da-Wei2020-06-091944-8244http://hdl.handle.net/1885/204873The 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.This work is financially supported by The University of New South Wales (UNSW), The University of Queensland (UQ), Chinese Academy of Sciences and Australian Research Council (ARC) Discovery Project (DP160103244). K.-H.W. thanks the support of the UNSW Faculty-Funded Research Fellowshipapplication/pdfen-AU© 2018 American Chemical Society201910.1021/acsami.8b163252019-12-19