Hierarchical Cu2S hollow nanowire arrays for highly efficient hydrogen evolution reaction

Abstract

Exploiting highly active and low-cost electrocatalysts based on earth-abundant elements for the hydrogen evolution reaction (HER) is an extremely desirable, but challenging task. Herein, we present a facile and economical two-step synthetic procedure to fabricate hierarchical Cu₂S hollow nanowire arrays implanted tightly on copper foam (Cu₂S HNAs-CF). Owing to the unique hierarchical hollow nanowire array nanostructure of a large surface area, copious active sites, easy mass/transport ability, and high conductivity, the as-synthesized hierarchical Cu₂S HNAs-CF electrode (as a self-supported electrode) shows excellent electrochemical HER activity with a low overpotential of 125 mV @ 100 mA cm⁻² in an alkaline electrolyte, and ranks as the top HER electrocatalyst reported. Upon coupling with the ordered macroporous RuO₂ (OMS-RuO₂), the Cu₂S HNAs-CF‖OMS-RuO₂/CF pair shows excellent performance for overall water splitting, which is significantly superior to those of most reported electrocatalysts and the commercial system PtC/CF‖RuO₂/CF.