A revolutionizing multifunctional CoMoO₄/MnMoO₄ oxide with highly selective methanol oxidation for boosting hydrogen evolution

This study presents the development of a high-performance bimetallic CoMoO₄/MnMoO₄ oxide-based electrocatalyst designed to revolutionize hydrogen production through highly selective methanol oxidation. A drop-casted, binder-free oxide film on a nickel foam substrate demonstrated exceptional electrocatalytic activity for the methanol oxidation reaction (MOR), significantly outperforming its individual oxide counterparts and their physical mixture. In an alkaline electrolyte, the CoMoO₄/MnMoO₄ film exhibited remarkably low MOR potentials of 1.26 and 1.40 V vs. reversible hydrogen electrode (RHE) at current densities of 10 and 100 mA cm⁻², respectively, compared to 1.56 and 1.68 V vs. RHE for the conventional oxygen evolution reaction (OER). Furthermore, the designed oxide electrode-based electrolyzer enabled the methanol oxidation toward a high selectivity of formate formation with an approximately 100 % faradaic efficiency for hydrogen evolution at 100 mA cm⁻². Operating the electrolyzer at 1.56 V and replacing the OER at the anode with MOR, the electricity consumption for hydrogen production was reduced from 4.57 kWh·m⁻³ to 3.73 kWh·m⁻³. Under this condition, a 20-fold increase in H₂ production was achieved and the cost of the electricity was lowered by 840 Watts per hour. Additionally, the CoMoO₄/MnMoO₄ film demonstrated superior stability under MOR conditions, making it a promising candidate for sustainable and cost-effective hydrogen production.