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

Abstract

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‐Fe3O4 catalyst. Following a “dissolution–redeposition” path, the defective FeOOH is formed under potential stimulation on the surface of the Cu‐Fe3O4 precursor during the electrochemical activation process. This Cu‐FeOOH/Fe3O4 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/Fe3O4 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‐Fe3O4 catalyst by means of an electrochemical activation method decreases the energy barrier of both H2O dissociation and H2 generation. Such a surface self‐reconstruction strategy provides a new avenue toward the production of efficient non‐noble metal catalysts for the HER.

In Situ Reconstructed Zn doped FexNi(1−x)OOH Catalyst for Efficient and Ultrastable Oxygen Evolution Reaction at High Current Densities

“…The reduced Fe ions subsequently reacts with OH − ions, leading to the electrosynthesis of FeOOH on post-OER electrode. [28,52,53] No obvious changes of the peaks associated with FeOOH/NiOOH is found in samples even after stability test under 1000 mA cm −2 for 1000h as shown in Figure 4d form the Ni species including the NiZn alloy and oxidized NF, while partial FeOOH is dissolved in alkaline electrolyte, leading to the unpurified KOH electrolyte. The generated NiOOH tends to rapidly merge with residue Zn-FeOOH film through covalent interaction.…”

Interfacial engineering of Cu–Fe2O3 nanotube arrays with built-in electric field and oxygen vacancies for boosting the electrocatalytic reduction of nitrates

“…2a). 45 Compared with Cu (932.4 eV and 952.2 eV for Cu 0 ), 46 the binding energy of Cu 0 in Cu–Fe 2 O 3 -60 appeared to have shifted slightly in the positive direction, indicating the decreased electron density of metal Cu in Cu–Fe 2 O 3 -60 due to electron loss. 47 Simultaneously, the slight negative shifts ( ca.…”

“…2a). 45 Compared with Cu (932.4 eV and 952.2eV for Cu 0 ), 46 side in the Cu-Fe 2 O 3 -60 (Fig. 2b).…”

Surface Reconstruction of Water Splitting Electrocatalysts

“…[144] As illustrated in Figure 14c, it could be identified that partially dissolved MoO 14d). [145] During the electrochemical activation process, part of the Fe 3 O 4 species was leached at the catalystelectrolyte interface and reacted with OH − to form an amorphous FeOOH phase on the precursor surface. By introducing Reproduced with permission.…”

“…Reproduced with permission. [145] Copyright 2022, Wiley-VCH. e) Evolution of phosphorus-doped carbon@MoP electrocatalysts during reconstruction process.…”