Electrochemically Reconstructed Cu‐FeOOH/Fe₃O₄ Catalyst for Efficient Hydrogen Evolution in Alkaline Media

Surface self‐reconstruction via incorporating an amorphous structure on the surface of a catalyst can induce abundant defects and unsaturated sites for enhanced hydrogen evolution reaction (HER) activity. Herein, an electrochemical activation method is proposed to reconstruct the surface of a Cu‐Fe 3 O 4 catalyst. Following a “dissolution–redeposition” path, the defective FeOOH is formed under potential stimulation on the surface of the Cu‐Fe 3 O 4 precursor during the electrochemical activation process. This Cu‐FeOOH/Fe 3 O 4 catalyst exhibits excellent stability as well as extremely low overpotential toward the alkaline HER (e.g., 129 and 285 mV at the large current densities of − 100 and 500 mA cm −2 , respectively), much superior to the Pt/C catalyst. The experimental and density functional theory calculation results demonstrate that the Cu‐FeOOH/Fe 3 O 4 catalyst has abundant oxygen vacancies, featuring optimized surface chemical composition and electronic structure for improving the active sites and intrinsic activity. Introducing defective FeOOH on the surface of a Cu‐Fe 3 O 4 catalyst by means of an electrochemical activation method decreases the energy barrier of both H 2 O dissociation and H 2 generation. Such a surface self‐reconstruction strategy provides a new avenue toward the production of efficient non‐noble metal catalysts for the HER.