Interface Engineering of Cu/Cu2O Nanowires on Cu Foam: Boosting C–H Bond Cleavage and Suppressing OH− Adsorption for Efficient Formaldehyde Electrooxidation

• • Cu/Cu2O@CF achieves 100 mA cm−2 at an ultra-low potential of −0.05 V vs. RHE, outperforming most reported FOR catalysts and enabling energy-efficient operation. • • The catalyst sustains 735 mA cm−2 at 0.6 V vs. RHE, overcoming the deactivation limit of conventional Cu-based catalysts above 0.5 V, ensuring high-current durability. • • Faradaic efficiencies for both formate and H2 production approach ~100%, indicating near-quantitative conversion of formaldehyde to valuable products. • • Coupling FOR with HER reduces hydrogen production energy consumption to 0.57 kWh m−3 H2, significantly lower than traditional water electrolysis, offering a cost-effective route for industrial hydrogen generation.