Efficient electrocatalytic chlorine evolution under neutral seawater conditions enabled by highly dispersed Co3O4 catalysts on porous carbon

Abstract

Chlorine evolution reaction (CER) is fundamental and critical for the conversion of Cl- to Cl2 in a seawater environment. However, the selectivity and electrocatalytic activity of non-precious metal-based catalysts in CER remain unsatisfactory. It is still a challenge to develop cost-effective and efficient CER electrocatalysts that can be produced in large scale. Herein, we proposed a metal-organic framework (ZIF-67) as a precursor for the synthesis of Co3O4 with a high specific surface area (SSA) and porous nano-sized. We then demonstrated for the first time that the porous nano-sized Co3O4 has high chlorine precipitation activity and stability. The potential (vs. Ag/AgCl) increased slightly from 1.225 to 1.258 V within 24 h of electrocatalytic reaction, and the Faraday efficiencies were higher than 80% at different current densities, indicating significant stability and selectivity. CER mechanism of the Co3O4 material under neutral seawater conditions was verified to be the Krishtalik mechanism by theoretical calculations.