Copper (0) Doping Makes Cobalt-Nickel Hydroxide a High-Efficiency Catalyst for Hydrogen Evolution Reaction

The improvement catalytic performance of nickel-cobalt-based catalysts for hydrogen evolution reaction (HER) is still challenging. In this work, the three dimensional metallic copper doped amorphous cobalt nickel hydroxide (Cu(0)-CoNi-OH) composite was deposited on nickel foam (NF) via a facile cyclic voltammetry method, and the doping effect of metal Cu on cobalt nickel hydroxide composite in Cu(0)-CoNi-OH for HER was studied systematically. It is found that the optimal as-prepared Cu(0)-CoNi-OH/NF electrode exhibits extraordinarily electrocatalytic activity for HER and it only requires an overpotential of 47 mV to reach a benchmark HER current density of 10 mA cm−2 in 1.0 M KOH. The prepared Cu(0)-CoNi-OH/NF electrode also exhibits extraordinary stability and fast reaction kinetics with a small Tafel slope of 48 mV dec−1. The excellent activity is attributed to the unique metal/hydroxide interfaces and the increased electrochemical activity surface area after Cu doping.