Systematic Study of the Electronic, Carbon, and N‑Doping Effects of CoMn-Oxide Composites as Bifunctional Oxygen Electrocatalysts
journal contributionposted on 27.08.2019, 18:36 authored by Ye Hu, Hengquan Chen, Xingmin Zhang, Wen Wen, Qinggang He, Chaohong He
Many cobalt-manganese oxides have been widely studied and reported to be excellent bifunctional oxygen catalysts for regenerative fuel cells and metal–air batteries. The studied materials include various shapes, compositions, and structures that have shown excellent bifunctional catalytic activity and stability. However, the structure–activity relationship of these catalyst materials has not been studied in-depth. The bifunctional activity of such catalysts is affected by many factors, and their specific morphology and composition determine their catalytic activity. The existing studies are fascinating but may lack implications for the design of better and more practical materials for bifunctional catalysts. Therefore, we have prepared binary cobalt-manganese oxides and corresponding nitrogen-doped carbon-based composite catalyst materials. By means of physical characterization, including X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy, combined with electrochemical characterization methods, various factors that affect the bifunctional catalytic activity of catalyst materials were systematically studied. The correlations between the electronic structure effect, carbon support effect, nitrogen-doping effect, and bifunctional catalytic activity are summarized.