Energy-efficient hydrogen production over a high-performance bifunctional NiMo-based nanorods electrode

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis
• Renewable Energy

Background:

• Electrochemical water splitting for hydrogen fuel is hindered by the sluggish oxygen evolution reaction (OER).
• Urea electrolysis offers a more energy-efficient pathway by replacing OER with urea oxidation reaction (UOR), but requires efficient catalysts.
• Existing non-noble metal catalysts often lack the required efficiency for industrial application.

Purpose of the Study:

• To develop a novel, highly efficient catalyst for urea oxidation reaction (UOR) and oxygen evolution reaction (OER).
• To investigate the potential of NiMo-based nanorods for energy-saving hydrogen production via urea electrolysis.
• To evaluate the catalytic activity and stability of the developed material for electrochemical applications.

Main Methods:

• Synthesis of Ni/Ni0.2Mo0.8N/MoO3 nanorods via thermal ammonolysis of a NiMo-based precursor.
• Electrochemical characterization including overpotential measurements for OER and hydrogen evolution reaction (HER).
• Evaluation of urea oxidation reaction (UOR) activity and stability in an alkaline electrolyte.
• Testing of a urea electrolysis cell utilizing the synthesized catalyst.

Main Results:

• The Ni/Ni0.2Mo0.8N/MoO3 catalyst exhibited low overpotentials for OER (252 mV) and HER (103 mV) at 10 mA cm-2.
• Exceptional UOR catalytic activity was observed, with a low potential of 1.349 V at 10 mA cm-2, surpassing commercial RuO2.
• Urea electrolysis using this catalyst achieved a significantly reduced cell voltage (1.356 V) compared to water electrolysis (1.52 V) with over 400 hours of stability.

Conclusions:

• The Ni/Ni0.2Mo0.8N/MoO3 nanorods demonstrate remarkable catalytic performance for both OER and UOR, attributed to synergistic effects.
• This novel catalyst offers a promising solution for energy-saving hydrogen production through efficient urea electrolysis.
• The material holds significant potential for large-scale energy applications and addressing urea-related wastewater treatment.