Metal-air batteries, particularly Zn-air batteries, have triggered considerable enthusiasm of communities due to their high theoretical power density. Developing highly active, cost-effective and alternative non-precious metal catalysts for the oxygen reduction reaction (ORR) is pivotal for popularizing zinc-air batteries. The rational design and synthesis of this type of catalyst are therefore critical, but it is still challenging to control the well-defined active sites as expected. Herein, we report a dual-nitrogen-source mediated route for synergistically controlling the formation of active Fe-N x moieties that are embedded in the carbon matrix. The facile control of coordination structures of precursors by this dual-nitrogen-source approach is revealed to play a key role in this report. Impressively, the optimized dual-nitrogen-source derived catalyst (i.e. Fe-N-C-800) exhibits prominently enhanced ORR activity with a half-wave potential of 0.883 V in alkaline electrolyte, higher by 32 mV and 72 mV than those derived from individual nitrogen sources, which is also further evaluated in primary Zn-air batteries. The enhanced ORR activity of Fe-N-C-800 is attributed to the rich Fe-N x active sites derived from the dual-nitrogen-source approach.
Wang, D., Xiao, L., Yang, P., Xu, Z., Lu, X., Du, L., … An, M. (2019). Dual-nitrogen-source engineered Fe-N x moieties as a booster for oxygen electroreduction. Journal of Materials Chemistry A, 7(18), 11007–11015. https://doi.org/10.1039/c9ta01953g