Nitrogen-coordinated single-atom catalysts with manganese and cobalt sites for acidic oxygen reduction†

Abstract

Developing a low-cost, highly active and durable catalyst for acidic oxygen reduction reaction (ORR) is of significant importance for proton-exchange electrolyte membrane fuel cell. In this work, we report an efficient catalyst based on Mn, Co and N co-doped carbon (MnCo-N-C) for acidic ORR. Electron microscopy and X-ray absorption spectroscopy indicate that atomic CoNx and MnNx sites are dispersed in the carbon matrices of MnCo-N-C. Raman spectroscopy verifies that the doping of Mn into carbon matrices can enable a higher graphitization degree, which can improve the corrosion resistance and catalytic durability of the MnCo-N-C catalyst towards ORR in challenging acidic media. As a result, the MnCo-N-C catalyst exhibits significantly improved ORR durability with a higher current retention of 81% after 50 h of test compared with that (52%) of the Co-N-C catalyst. Moreover, the half-wave potential of the MnCo-N-C catalyst increases by 100 mV compared with that of the Co-N-C catalyst.