Decoupled Biomass Electrooxidation Over E‐Waste‐Derived Au Enables Low‐Voltage H 2 and Scalable FDCA Production

ABSTRACT The oxygen evolution reaction (OER) constitutes a major energetic bottleneck in electrochemical hydrogen production. Replacing OER with low‐potential organic oxidation provides an effective route to reduce cell voltage while enabling value‐added chemical synthesis. Here, a nanostructured Au electrocatalyst is developed from recycled electronic waste via a corrosion‐template–assisted electrodeposition strategy. Co(OH) 2 nanoarrays grown on nickel foam act as a sacrificial template to regulate galvanic displacement between chloride‐coordinated Au(III) species and metallic Ni, inducing polycrystalline Au nucleation with tailored surface structures. Subsequent electrodeposition precisely controls Au size and dispersion, resulting in a substantially enlarged electrochemically active surface area. In alkaline media, the Au electrode selectively drives aldehyde oxidation of 5‐hydroxymethylfurfural to 5‐hydroxymethyl‐2‐furoic acid at potentials well below those required for OER, while enabling concurrent anodic hydrogen evolution and stable low‐voltage bipolar hydrogen production. In a flow‐electrolysis configuration, current densities of ∼0.6 A cm −2 are sustained at a low cell voltage of ∼1.2 V for over 200 h. By decoupling low‐potential aldehyde oxidation from high‐potential deep oxidation in a tandem electrolyzer, stepwise electrochemical upgrading from HMF to FDCA is achieved with reduced overall energy input. This work establishes a scalable electrochemical platform that integrates low‐voltage hydrogen production with high‐value biomass conversion.