NixCu1−x/CuO/Ni(OH)2 as highly active and stable electrocatalysts for oxygen evolution reaction

Abstract

Ni–Cu alloy-based nanomaterials are representative cost-effective materials that have been widely used as highly active and stable electrocatalysts for electrochemical energy applications, such as the water oxidation reaction, the methanol/ethanol reaction and many other small molecule oxidation reactions. Here, novel short needle-like complex oxides of Ni_xCu_1−x/CuO/Ni(OH)₂ are rationally designed and synthesized to further promote their oxygen evolution reaction (OER) performance. Under the tuning of electron perturbation and surface morphology, Ni_0.7Cu_0.3/CuO/Ni(OH)₂ reached an optimum performance of ∼136.6 mV_RHE kinetic potential and ∼160 mV_RHE (vs. 3.33 A g⁻¹) over-potential with a Tafel slope of 66 mV dec⁻¹. Furthermore, the complex oxides are directly grown on glass carbon, which works as a binder-free and carbon-free electrode, leading to an excellent stability of 200 000 s with 39% activity loss. Due to the electron perturbation role of Cu as well as the synergistic interactions among Ni–Cu, CuO and Ni(OH)₂, the obtained Ni_0.7Cu_0.3/CuO/Ni(OH)₂ complex oxide is significantly more active and stable than those of Ni_xCu_1−x alloy, CuO and Ni(OH)₂. Our results demonstrate a general strategy to design cost-efficient OER electrocatalysts by using a conventional and easily accessible Ni_0.7Cu_0.3/CuO/Ni(OH)₂ hybrids to possibly replace commercial Ru/Ir-based materials.