Boosting Oxygen Reduction Activity of Co3O4 through a Synergy of Ni Doping and Carbon Species Dotting for Zn-air Battery

Abstract

Oxygen reduction reaction (ORR) undertakes an indispensable driving role for metal-air batteries with sluggish kinetics. In this work, we proposed a synergic strategy of Ni doping and carbon species dotting to compose Co3O4 with intrinsic large specific area and oxygen vacancies. The Ni-doped Co3O4/C (NCC-1) with four electron transfer mode conducts extraordinary electrocatalytic performance than commercial 20 wt% Pt/C and excellent tolerance to methanol poisoning. This series of improvements are attributed to the rapid dynamics drove by variable transition metal valence with elevated electronic conductivity derived from dotted carbon species. The XPS results at different reduction stages investigate that the doped Co3O4/C affects ORR performance by adjusting the species of *O at the active sites and the formation of intermediates including *OH and *O. More Co3+ active sites exposed on the NCC-1 surface, higher catalytic activity is provided by the conversion of Co(Ⅱ)/Co(III) and Ni(Ⅱ)/Ni(III). What is purposeful in practicability. the NCC-1/IrO2 based Zn-air batteries show an excellent charge-discharge response and cyclability than that of 20% Pt/IrO2 based Zn-air batteries, highlighting the implemented potentiality of NCC-1 based metal-air-battery. This study offers new insights into designing non-noble-metal based oxygen reduction electrocatalysts for more energy storage devices.