Dual Modulation via Electrochemical Reduction Activiation on Electrocatalysts for Enhanced Oxygen Evolution Reaction

Cobalt-based spinels are promising candidates for oxygen evolution reaction (OER). However, these electrocatalysts usually suffer from the lack of active species transformation during OER due to the high stability and reversibility of the spinel structure. Herein, we highlight that electrochemical reduction could serve as a general activation process with dual modulation on spinels and enhance the catalytic activity. Taking Co3O4 as an example, both rock salt generation and increased surface roughness could be realized. Moreover, because of the synergistic effect of dual modulations, surface rock salt could be massively generated, which breaks the scale limitation of chemical reduction. With optimal modulation, electrochemically reduced Co3O4 showed lower overpotential and enhanced OER activity. Furthermore, electrochemical reduction activation could be extended to other spinel oxides. We anticipate that electrochemical reduction activation will be a facile route to realize efficient electrocatalytic performance, offering new insights toward the correlation among processing methods, active sites, and catalytic performance.