Enhancing the Stability of Cu‐Based Electrocatalyst via Fe Alloy in Electrocatalytic Formaldehyde Oxidation with Long Durability

Abstract Electrocatalytic formaldehyde oxidation with metal Cu electrocatalyst has attracted significant interest since it can produce H ₂ at the anode and make it possible to construct a bipolar hydrogen production cell with low voltage. However, the activity of the Cu electrocatalyst will be greatly weakened after oxidizing it to Cu ⁺ or Cu ²⁺ . Here, a CuFe bimetallic catalyst is developed to efficiently catalyze the electro‐oxidation process of HCHO to produce H ₂ at a potential of 0.10 V _RHE with a current density of 100 mA cm ⁻² . It is confirmed that introducing Fe in a CuFe catalyst can regulate the electron configuration to prevent Cu ⁰ oxidation and improve the stability of the catalysts. The introduction of Fe can reduce the energy barrier of the reaction process, and make the C─H bond more easily split on CuFe. A bipolar hydrogen production device is constructed by combining the anodic oxidation of HCHO with the cathodic hydrogen evolution. The current density of 500 mA cm ⁻² is achieved at a cell voltage of 0.6 V. The faradaic efficiency is ≈100% and the device is stable for ≈50 h. The research provides a promising path toward the secure, effective, and expandable generation of high‐purity H ₂ at both anodic and cathodic electrodes.