Nitrogen-doped MoO2/Cu heterojunction electrocatalyst for highly efficient alkaline hydrogen evolution reaction

Abstract

Metal/metal-(hydr)oxide heterojunction has been proposed as an efficient means to enhance the kinetics of alkaline hydrogen evolution reaction (HER). However, the poor electronic conductivity of metal-(hydr)oxides hinders the transport of electrons and the inappropriate electronic structure of the constituent phases would lower the HER activity. Herein, a nitrogen-doped MoO2/Cu heterostructure nanosheets was prepared by a simple hydrothermal and subsequent annealing treatment, acting as a model catalyst for element-doped modified metals/metal-oxides composite towards alkaline HER. Experimental results revealed that the HER catalytic activity of the catalyst was effectively improved by the nitrogen doping and the hetero coupling effect. The obtained N–MoO2/Cu catalyst exhibited a low overpotential of 40 and 363 mV to drive the current densities of 10 and 1000 mA cm−2, respectively, and showed high stability in the constant-current test of 50 h at 10 mA cm−2, 100 mA cm−2 and 1000 mA cm−2. Impressively, the N–MoO2/Cu catalyst coupled with Ni–Fe LDH to assemble an alkaline electrolyzer only require a voltage of 1.49 V to achieve a current density of 10 mA cm−2, and could be actuated by wind power to continuously produce hydrogen.