Selective preparation of CoNi (111) crystal plane to improve hydrogen production by water electrolysis

The development of hydrogen energy can significantly reduce reliance on fossil fuels by providing a sustainable hydrogen production pathway. The aim of this study is to selectively prepare CoNi (111) crystal plane catalyst instead of other crystal planes from nickel‑cobalt containing waste to improve the properties of hydrogen evolution reaction by electrolytic water. During the catalyst preparation process, the reduction order and reduction efficiency of Ni²⁺, Co²⁺ and H₂O in the nickel‑cobalt containing waste leachate were controlled to regulate the electrodeposition of Ni²⁺ and Co²⁺, and the generation of crystal planes of CoNi(111). According to the electrocatalytic performance test, the prepared catalyst under conditions of 10 min, c(Ni²⁺) = 0.05 mol/L, 40 mA/cm², m(NiSO₄): m(CoSO₄) = 1:1 has excellent activity, an overpotential of 16.5 mV is required at a current density of 10 mA/cm², and a Tafel slope of 66.5 mV/dec. In this work, using nickel‑cobalt-containing waste as a raw material for catalyst synthesis can not only reduce the cost, but also reduce the harm to the environment. Therefore, this study provides an environmentally friendly and economical method for the preparation of a high-performance and low-cost catalyst for hydrogen evolution reaction.