Electrodeposited Trimetallic NiFeW Hydroxide Electrocatalysts for Efficient Water Oxidation

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Developing efficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for alkaline water oxidation.
• Nickel-iron hydroxides are promising OER catalysts, but their performance can be further enhanced.
• Tungsten doping offers a strategy to modulate the electronic properties and active sites of Ni-Fe based materials.

Purpose of the Study:

• To investigate the efficacy of tungsten-doped Ni-Fe hydroxides as electrocatalysts for the oxygen evolution reaction (OER).
• To understand the role of tungsten incorporation in enhancing catalytic activity and stability.
• To compare the performance of the developed catalyst against state-of-the-art iridium-based catalysts.

Main Methods:

• Fabrication of tungsten-doped Ni-Fe hydroxides on three-dimensional nickel foam via cathodic electrodeposition.
• Electrochemical characterization, including overpotential measurements and Tafel slope analysis, to evaluate OER activity.
• Long-term chronopotentiometry to assess catalyst stability and surface evolution.

Main Results:

• Tungsten doping modulates the electronic structure of Ni-Fe hydroxides, creating oxygen vacancies and abundant active sites.
• The optimized W-doped Ni-Fe hydroxide catalyst exhibits superior OER activity compared to 20 wt% Ir/C.
• Achieved low overpotentials (224 mV for 10 mA cm⁻² and 251 mV for 50 mA cm⁻²) with a low Tafel slope.
• Post-chronopotentiometry analysis shows tungsten reduction stabilizes active sites for sustained water oxidation.

Conclusions:

• Tungsten doping is an effective strategy to enhance the electronic coupling and catalytic performance of Ni-Fe hydroxides for OER.
• The W-doped Ni-Fe hydroxide catalyst demonstrates excellent activity and stability, outperforming commercial Ir/C catalysts.
• This work provides insights into optimizing tungsten doping for advanced electrocatalyst design in water splitting applications.