Spinel ZnCo2O4 Nanosheets Supported on Ni Foam as Electrocatalysts for the Oxygen Evolution Reaction

Abstract

Oxygen evolution reaction (OER) involves the multistep atomic coupling electron transfer process, which serves as the rate-limiting step in electrocatalytic water splitting. Hence, the design of OER catalysts with high performance and stability represents a critical factor in promoting the oxygen evolution reaction. In this study, ZC/NF-m_n catalysts were fabricated by the hydrothermal method, achieving the in situ growth of spinel active phase (ZnCo₂O₄) on the three-dimensional porous skeleton of nickel foam. Among these catalysts, the ZC/NF-m₂ catalyst requires an overpotential of only 222 mV at a current density of 10 mA·cm^–2 in neutral medium. Multiple characterization results demonstrate that the OER performance of the ZC/NF-m₂ catalyst with ZnCo₂O₄ phase is superior to that of the single metal oxides (Co₃O₄ and ZnO) owing to the synergistic effects of the multicomponent system. More importantly, an appropriate growth amount of the spinel active phase not only optimizes the morphology properties but also provides abundant oxygen vacancies and Co²⁺–O_v structures on the catalyst surface, which are crucial for the adsorption of molecular oxygen and electron transfer during the oxygen evolution process. The ZC/NF-m₂ catalyst with excellent stability and efficient electrocatalytic performance presents a design strategy for developing non-precious-metal materials for oxygen evolution reaction.