Turning on Zn 4s Electrons in a N -Zn-B Configuration to Stimulate Remarkable ORR Performance.

A zinc-based single-atom catalyst has been recently explored with distinguished stability, of which the fully occupied Zn 3d electronic configuration is Fenton-reaction-inactive, but the catalytic activity is thus inferior. Herein, we report an approach to manipulate the s-band by constructing a B,N co-coordinated Zn-B/N-C catalyst. We confirm both experimentally and theoretically that the unique N -Zn-B configuration is crucial, in which Zn (3d 4s ) can hold enough delocalized electrons to generate suitable binding strength for key reaction intermediates and promote the charge transfer between catalytic surface and ORR reactants. This exclusive effect is not found in the other transition-metal counterparts such as M-B/N-C (M=Mn, Fe, Co, Ni and Cu). Consequently, the as-obtained catalyst demonstrates impressive ORR activity, along with remarkable long-term stability in both alkaline and acid media. This work presents a new concept in the further design of electrocatalyst.