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

Abstract

Hydrogen (H₂) 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 H₂. 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.