Ruthenium-doped Ni(OH)2 to enhance the activity of methanol oxidation reaction and promote the efficiency of hydrogen production

Abstract

The coupling of the hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR) to produce clean hydrogen energy with value-added chemicals has attracted substantial attention. However, achieving high selectivity for formate production in the MOR and high faradaic efficiency for H₂ evolution remain significant challenges. In light of this, this study constructs an Ru/Ni(OH)₂/NF catalyst on nickel foam (NF) and evaluates its electrochemical performance in the MOR and HER under alkaline conditions. The results indicate that the synergistic effect of Ni(OH)₂ and Ru can promote the catalytic activity. At an overpotential of only 42 mV, the current density for the HER reaches 10 mA cm⁻². Moreover, in a KOH solution containing 1 M methanol, a potential of only 1.36 V vs. RHE is required to achieve an MOR current density of 10 mA cm⁻². Using Ru/Ni(OH)₂/NF as a bifunctional catalyst, employed as both the anode and cathode, an MOR-coupled HER electrolysis cell can achieve a current density of 10 mA cm⁻² with a voltage of only 1.45 V. Importantly, the faradaic efficiency (FE) for the hydrogen production at the cathode and formate (HCOO⁻) production at the anode approaches 100%. Therefore, this study holds significant practical implications for the development of methanol electro-oxidation for formate-coupled water electrolysis hydrogen production technology.