Inducing oxygen vacancies using plasma etching to enhance the oxygen evolution reaction activity of the CoMn2O4 catalyst

Spinel-type AB2O4 material has considerable potential as an efficient electrocatalyst in the oxygen evolution reaction (OER). However, developing spinel-type catalysts with higher catalytic activity still faces significant challenges. Herein, we reported an effective strategy to construct abundant oxygen vacancies into the CoMn2O4 (CMO) catalyst using plasma etching, and those oxygen vacancies were capable of enhancing the OER activity of the CMO catalyst. The results showed that the etched CMO catalyst possessed an overpotential of 367 mV at a current density of 10 mA/cm2, and the change overpotential of the etched CMO catalyst was only about half compared to that of the pristine CMO catalyst in a 24-h stability test. The charge transfer ability and reaction kinetic characteristic of the etched CMO catalyst were dramatically improved. Furthermore, the mechanism of oxygen vacancies inducing enhancement of the OER catalytic activity in CMO catalysts has also been elucidated. This work successfully used a defect engineering strategy for modifying the spinel-type catalyst to enhance its OER activity, thereby providing a new idea and method for developing more efficient OER catalysts.