A Co/CoO hybrid rooted on carbon cloth as an efficient electrocatalyst for the hydrogen evolution reaction in alkaline solution

Abstract

The development of low-cost electrocatalysts with high performance toward the hydrogen evolution reaction (HER) is crucial for large-scale and clean hydrogen production. Herein, we report a facile synthesis of Co/CoO hybrids with oxygen vacancies on carbon cloth (CC) via the calcination treatment of a Co₃O₄ precursor in a reducing atmosphere (H₂/Ar). Moreover, to avoid delamination and cracks during heat treatment and catalyst abscission during the HER test, the precursor of Co(OH)₂ was stabilized on CC by the anion intercalation method, resulting in robust adhesion between the film and substrate. The as-prepared Co/CoO hybrids rooted on the CC substrate possessed good charge transfer properties, favorable kinetics, abundant active sites, and robust adhesion. A suitable reducing atmosphere was crucial for high catalytic activity. By optimizing, the sample obtained in a 30% H₂/Ar atmosphere (Co/CoO-30) possessed an optimal balance between Co/CoO and oxygen vacancies, exhibiting optimum HER performance with the smallest overpotential of 158 mV at 10 mA cm⁻² and Tafel slope of 68.1 mV dec⁻¹ as well as good stability, operating for at least 24 h.