Modulating the Electronic Structure of Zinc Single Atom Catalyst by P/N Coordination and Co2p Supports for Efficient Oxygen Reduction in Zn-Air Battery

Abstract

Single-atom catalysts have emerged as effective active species for electrocatalysis because of their appropriate structural and electronic properties. In this work, we synthesized Zn single atoms with a configuration of ZnN 3 P in the carbon framework. With the Co 2 P particles as supports (ZnCo-PNC), the generic Zn single atom catalysts with a content of only 2wt% showed a half-wave potential of 0.91 V for oxygen reduction reaction in alkaline medium, even better than commercial Pt/C (0.87 V). DFT results demonstrated that the synergistic promotion of Co 2 P supports and N/P coordination could reduce the energy barrier to proceed ORR on Zn single atoms from 1.85 to 0.79 eV. By using it as the cathode catalyst for zinc-air battery application, it shows respectable performance in terms of maximum peak power (237.3 mW cm -2 ) and energy densities (847 W h kg -1 ).

Keywords: Single metal atom, Dual coordination, Synergistic effect, oxygen reduction reaction, zinc-air battery.