Modulating Urea Oxidation by Iron-Accelerated Reconstruction and Tailoring Anionic Microenvironment

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Anodic small-molecule electro-oxidation is key for hydrogen production and chemical synthesis.
• Nickel-based anodes for urea oxidation (UOR) face challenges like slow reconstruction, poisoning, and mass transport limits.

Purpose of the Study:

• To engineer Fe-doped Ni3S2 nanosheet arrays for efficient UOR.
• To develop a strategy for regulating the active site and anionic microenvironment.

Main Methods:

• Fabrication of self-supported Fe-doped Ni3S2 nanosheet arrays.
• Operando spectroscopy and electrochemical analyses.
• Investigating the role of Fe dopants and interfacial sulfate layers.

Main Results:

• Fe dopants accelerate Ni(Fe)OOH formation and anion-derived reconstruction.
• An interfacial SO4(2-) layer mediates electron transfer and suppresses carbonate adsorption.
• Optimized electrode achieves 200 mA cm-2 at 1.355 V for UOR and 59 mV overpotential for hydrogen evolution.

Conclusions:

• The Fe-doped Ni3S2 electrode demonstrates enhanced UOR activity and bifunctional hydrogen evolution.
• The mechanism-driven strategy of interfacial gating and coreconstruction offers a transferable blueprint for electro-oxidation reactions.