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 Ce_0.15La_0.85Ni_0.3Co_0.7O₃ 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.