The active structure of p-block SnNC single-atom electrocatalysts for the oxygen reduction reaction

adsorption and bonded at the Sn-C bridge site as a part of the active center to promote the associative four-electron ORR. The active Sn center has a Sn(II) ion-like character, and the partially filled p-bands around the Fermi level and the fully filled s-bands of Sn control the strength of the bond with ORR intermediates. Our theoretical findings rationalized the active nature of the observed high four-electron reactivity of SnNC electrocatalysts, which will promote the rational design of other efficient main-group-metal SACs.