Geometrical configuration modulation via iron doping and defect engineering in spinel oxides for enhanced oxygen revolution activity

Abstract

Electronic structure engineering is considered to be the heart of the development of efficient electrocatalysts. Most studies focus on one technique and optimal electronic states are still unsatisfied. Herein, Fe dopants and oxygen vacancies (VO) are introduced to Co3O4, and the resultant defective CoOx-Vo-DFe catalyst exhibits splendid catalytic activity toward oxygen evolution reaction (OER). It endows an overpotential of 192 mV at 10 mA cm−2 and Tafel slope of 42.53 mV dec−1, outperforming the Fe-free sample CoOx-Vo (322 mV, 107.9mV dec−1) and poor defective counterpart CoOx-DFe (314 mV, 59.96mV dec−1). The results reveal that Fe doping and oxygen defect engineering along with the formation of hetero-interface tune synergistically the electronic configuration to more active state and enhance the electronic conductivity, resulting in dramatically decreased binding energy of OOH*, and consequently much lower electrocatalytic overpotential. The subtle combination of multiple modification strategies is beneficial to approaching the activity limit of electrocatalysts for various electrochemical energy devices.