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 CoN_x and MnN_x 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.