Nanosheet arrays derived from ZIF-67 grown on three-dimensional frameworks for the electrocatalytic oxygen evolution reaction†

Abstract

Hydrogen energy has become one of the most promising substitutes for conventional fuels because of its high calorific value and green and renewable advantages. Among various hydrogen production strategies, the water splitting hydrogen production strategy stands out. Therefore, it is very important to develop efficient and cheap oxygen evolution reaction (OER) electrocatalysts for hydrogen production by electrolysis of water. In this work, nickel selenide grown on nickel foam (NF) with good electrical conductivity and excellent catalytic performance, i.e. NiSe_x/NF, was selected as the three-dimensional conducting substrate, and the active material ZIF-67 was successfully compounded on the conductive substrate by using the in situ growth strategy. A series of self-supporting materials ZIF-67/NiSe_x/NF were obtained, which can be directly used as working electrodes for the electrocatalytic OER. The self-supporting material ZIF-67/NiSe_x/NF-1 can achieve a low overpotential of 353 mV at a current density of 100 mA cm⁻² with a small Tafel slope of 107 mV dec⁻¹, and excellent stability for 55 hours of continuous OER at a current density of 50 mA cm⁻² in an alkaline medium. Benefiting from the unique layered structure and the synergy between Co and Se optimizing the electronic structure, ZIF-67/NiSe_x/NF-1 when used directly as an electrode shows exceptional OER catalytic performance at high current density.