Ion-induced Effect of Ce, Ni Dual Site Doped LaCoO3 Catalyst for Efficient Electrocatalytic Water Oxidation

Abstract

Perovskite oxides exhibit excellent performance in water oxidation, but still lacks a precise regulation strategy for the active sites, while the reaction mechanism is poorly understood. Herein, an ion-induced effect (IIE) is proposed of Ce, Ni dual site doped LaCoO3(CeNi-LaCoO3), where Ni2+ induces the binding of Co species into bimetallic sites, and Ce4+ induces the activation of Co species and reduces the Co-O binding energy. Benefiting from the IIE of Ni2+ and Ce4+, the optimized Ce0.15La0.85Ni0.3Co0.7O3 exhibits excellent OER performance with an overpotential of only 330 mV when the current density reached 10 mA cm−2, the Tafel slope of 70.93 mV dec−1 as well as good stability. Theoretical calculations further reveal that the OER occurring on CeNi-LaCoO3 follows the LOM mechanism, and IIE caused by the doping of the Ce, Ni dual site induces the conversion of Co2+ to Co3+, optimizes the electron arrangement, modulates the electron transfer capacity of the Co site, promotes the conversion of lattice oxygen to OH−, lowers the energy barrier for the participation of bulk oxygen in the OER, and thus promotes the OER performance. This work is expected to provide reliable support for the application of high-efficiency perovskite-based OER catalysts.