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 H₂ 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 Cu²⁺. Here, a CuFe bimetallic catalyst is developed to efficiently catalyze the electro-oxidation process of HCHO to produce H₂ 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 Cu⁰ 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 H₂ at both anodic and cathodic electrodes.