Electrochemically activated Cu2O/Co3O4 nanocomposites on defective carbon nanotubes for the hydrogen evolution reaction

Hydrogen (H-2) is an alternative clean and sustainable energy source that could alleviate the fossil fuels crisis, and eco-friendly water electrolysis has been widely employed to produce H-2. Herein, we report for the first time the facile synthesis of copper(I) oxide and cobaltosic oxide hybrid nanocomposites decorating defective carbon nanotubes (Cu2O/Co3O4/DC) using a hydrothermal method. Notably, the electrocatalysis of Cu2O/Co3O4/DC is significantly improved through an electrochemical activation process. The electrochemically activated Cu2O/Co3O4/DC (ECA-Cu2O/Co3O4/DC) presents excellent HER activity and durability with a small overpotential of 160 mV at a current density of 10 mA cm(-2) and a small Tafel slope of 73 mV dec(-1). This high hydrogen evolution performance is attributed to the synergistic interaction between Cu2O/Co3O4 nanoparticles and defective carbon nanotubes, providing further understanding of earth-abundant transition metal-bearing electrocatalysts in emerging energy applications.