Sn-Mediated Amorphous NiFeP Electroless Plating on Nickel Mesh for Stable High-Current Oxygen Evolution Reaction

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Commercialization of water electrolysis for hydrogen production is constrained by the performance and cost of oxygen evolution reaction (OER) electrodes.
• Nickel-iron phosphide (NiFeP) shows promise as an alkaline OER electrocatalyst but suffers from poor activity at high current densities, instability, and challenges in uniform loading on nickel mesh (NM).
• Robust and scalable electrode fabrication methods are critical for advancing industrial-scale water electrolysis.

Purpose of the Study:

• To develop a novel, low-cost, and scalable method for preparing high-performance NiFeP OER electrocatalysts on NM.
• To improve the activity, stability, and loading uniformity of NiFeP electrocatalysts for industrial water electrolysis applications.
• To address the limitations of existing NiFeP catalysts in alkaline media, particularly at high current densities.

Main Methods:

• An electroless plating technique using tin (Sn) as a promoter was employed under low-temperature conditions.
• In situ growth of amorphous nickel-iron-phosphorus (NiFeP) on a smooth nickel mesh (NM) surface was achieved, forming NiFeP-Sn/NM.
• The morphology and composition of the catalyst were analyzed, and its electrochemical performance was evaluated for OER in alkaline media.

Main Results:

• The NiFeP-Sn/NM catalyst exhibited significantly enhanced OER performance, requiring only 309 mV overpotential to drive 100 mA cm^-2, compared to NiFeP/NM (332 mV) and Ni/NM (460 mV).
• Tin oxide (SnO₂) acted as a core, facilitating deposition, preventing leaching, and promoting stable NiFeP agglomerates, thereby balancing activity and stability.
• Stable operation at a high current density of 500 mA cm^-2 was demonstrated during prolonged electrolyzer testing, with the cell voltage maintained around 1.9 V without overpotential decay.

Conclusions:

• The developed low-temperature electroless plating method using Sn promoter effectively solves the loading issues of NiFeP on NM, enabling uniform and robust catalyst deposition.
• The NiFeP-Sn/NM catalyst offers excellent industrial OER performance, characterized by high activity and exceptional long-term stability under demanding conditions.
• This cost-effective and scalable approach provides a feasible route for the industrial production of high-performance OER electrodes, significantly advancing water electrolysis commercialization.