Hetero-Anionic Structure Activated Co-S Bonds Promote Oxygen Electrocatalytic Activity for High-Efficiency Zinc-Air Batteries.

The electronic structure of transition metal complexes can be modulated by replace partial ion of complexes to obtain tuned intrinsic ORR (Oxygen Reduction Reaction) or OER (Oxygen Evolution Reaction) electrocatalytic activity. However, the anion-modulated transition metal complexes ORR activity of is still unsatisfactory, and the construction of hetero-anionic structure remains challenging. Herein, we present an atomic doping strategy to prepare the CuCo 2 O 4-x S x /NC-2 (CCSO/NC-2) as electrocatalysts, combined XRD, HAADF-STEM images and XAFS results favorably demonstrate the partial substitution of S atoms for O in CCSO/NC-2, which shows excellent catalytic performance and durability for OER and ORR in 0.1 M KOH. For ORR, CCSO/NC-2 exhibits a half-wave potential of 0.75 V and lower Tafel slope (69.3 mV dec -1 ), while for OER, CCSO/NC-2 exhibits a low overpotential (340 mV) at 10 mA cm -2 , a small Tafel slope (121.3 mV dec -1 ). In addition, the catalyst assembled zinc-air battery with an open circuit potential of 1.43 V maintains performance after 300 h of cyclic stability. DFT calculations and differential charges illustrate that S doping optimizes the reaction kinetics and promotes electron redistribution. The superior performance of CCSO/NC-2 catalysis is mainly due to its unique S modulation of the electronic structure of the main body. The introduction of S promotes Co-O covalency and constructs a fast electron transport channel, thus optimizing the adsorption degree of active site Co to the reaction intermediates. This article is protected by copyright. All rights reserved.