Manipulating the coordination dice: Alkali metals directed synthesis of Co-N-C catalysts with CoN sites.

Nitrogen-coordinated metal sites (MN) in metal- and nitrogen-codoped carbon (M-N-C) catalysts offer promising electrocatalytic activity, but selective synthetic design of MN sites with specific coordination environments remains challenging. Here, we manipulate the formation statistics of MN sites by using sacrifice alkali metals (AM = Li, Na, and K) to form metal vacancy-N carbon (AM-MVN-C) templates, which are used to direct the solution-phase formation of CoN sites in Co-N-C catalysts. We build a probability weight function based on the embedding energy of M in MN sites as the descriptor for MN formation statistics, and we predict that the alkali metals are prone to induce the formation of MVN sites. By coordinating Co ions with AM-MVN-C templates, we synthesize Co-N-C with CoN sites, demonstrating remarkable oxygen reduction activity in anion exchange membrane fuel cells. These results highlight the statistical thermodynamics of MN formation and open up the possibility for the rational design of complex M-N-C electrocatalysts with well-defined MN sites.