The carbon-supported nitrogen coordinated metal single-atom catalyst M-N-C is currently the most active type of non-platinum catalysts. However, the fuel cell activity of this type of catalyst is still less than 1/10 of that of the platinum-based catalyst. The more serious problem is the high-activity M-N-C catalysts have fast performance degradation, which limits their practical application. Taking the atomic active sites of M-N<sub>x</sub> as the object, we studied the effects of active site coordination number, intrinsic activity, active site concentration and utilization on fuel cell performance, and revealed the coordination principle of the active site. It was found that low utilization of active sites is a key limiting factor. In addition, a solid synthesis method has been invented to produce multi-metal M-N-C catalysts with high-density of active sites, including ferrous metals, platinum group metals and rare earth metals. In terms of Fe-N-C stability, it was found that the reduction in the coordination number of Fe-N<sub>4</sub> active sites rather than iron loss is the main reason for the rapid decay in the initial performance of Fe-N-C fuel cells. The active site repair method and protection strategy are proposed. The metal-free carbon-based catalysts demonstrate better fuel cell stability.

Activity and stability of M-N-C catalysts in PEM fuel cell

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.