Manipulation of oxygen evolution reaction kinetics of a free-standing CoSe2–NiSe2 heterostructured electrode by interfacial engineering

Abstract

Electrodeposition is a facile and scalable strategy to prepare free-standing oxygen evolution reaction (OER) electrodes with promising electrocatalytic activity, high active site utilization, and fast mass transportation. In this study, hierarchical CoSe₂–NiSe₂ heterostructured nanosheets were electrodeposited on three-dimensional Ni foam (NF) via deliberate interface engineering using a two-step potentiostatic route. Morphological analysis confirms that CoSe₂–NiSe₂ has a hierarchical nanosheet-like morphology, and the surface is composed of NiSe₂ (210) and CoSe₂ (210) planes. The heterostructure CoSe₂–NiSe₂/NF electrocatalyst has a remarkably improved OER performance with a low overpotential of 160 mV at 10 mA cm⁻² in alkaline media compared to the monometallic Co-based electrocatalyst CoSe₂/NF (290 mV@10 mA cm⁻²) and Ni-based electrocatalyst NiSe₂/NF (310 mV@10 mA cm⁻²). Thus, the strong interface interaction between CoSe₂ and NiSe₂ in heterostructured CoSe₂–NiSe₂/NF is essential for high OER performance. Furthermore, the heterostructured electrocatalyst exhibits high stability during 2000 potential cycles and a 5 h chronoamperometric test. The excellent OER performance is attributed to the high electrochemical active area and synergistic effect of the bimetallic selenide-heterojunction. This work offers a facile and scalable strategy for exploiting synergistic electrocatalysis based on heterostructured electrocatalysts, as well as novel instances for the utilization of efficient, low-cost, and non-toxic electrocatalysts in the water-splitting process.