Active site engineering by surface sulfurization for a highly efficient oxygen evolution reaction: a case study of Co3O4 electrocatalysts

Abstract

In this work, a surface sulfurization strategy is utilized to construct Co₃O₄@CoS_x heterogeneous catalysts with a highly efficient activity towards the oxygen evolution reaction (OER), and the enhanced catalytic activity is dependent on the degree of surface sulfurization. It is found that forming amorphous CoS_x on the Co₃O₄ surface through surface anion exchange can effectively generate more Co²⁺ ions and oxygen vacancies in the lattice structure, not only inducing the production of more CoOOH but also facilitating water adsorption during the water oxidation process.