Improvement of electrocatalytic properties of copper nanofoam modified by coral reef-like nickel-cobalt electrocatalyst for water splitting

Synthesis of a stable and efficient electrocatalyst for hydrogen evolution reaction (HER) using earth-abundant elements and inexpensive regents is essential to produce green H₂ as an alternative to fossil fuels. In this study, a novel electrocatalyst has been developed using a Cu-foam substrate with a large surface area and electrochemically modified by Ni-Co bimetallic catalyst. A simple and effective two-step electrodeposition method has been applied using a solution of Ni and Co precursors to form NiCo@Cu-foam electrode. The SEM results indicated a porous structure for Cu-foam substrate with numerous active sites for the electrodeposition of Ni-Co electrocatalyst. The synergistic effect of Ni, Co, and Cu atoms with high conductivity and low overpotential has made NiCo@Cu-foam an excellent electrocatalyst. Remarkably, in 0.5 M H₂SO₄ acidic media, NiCo@Cu-foam electrode showed increased electrocatalytic activity to provide a current density of 100 mA.cm⁻² compared to the corresponding values for Co@Cu-foam and Ni@Cu-foam electrodes at − 0.12, − 0.16, and − 0.19 V vs. RHE. Moreover, the fabricated catalyst showed a low Tafel slope of 67 mV.cm⁻¹ and outstanding long-term stability for H₂ evolution without considerable decrease at different overpotentials and current densities. The present study introduced an attractive candidate with improved performance for water splitting and clean energy production fabricated by inexpensive starting materials.

Keywords: Hydrogen evolution Electrodeposition Synergistic effect Cu-foam Ni-Co electrocatalys