A durable and pH-universal self-standing MoC-Mo₂C heterojunction electrode for efficient hydrogen evolution reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient water electrolyzers require low-cost, earth-abundant hydrogen evolution reaction (HER) catalysts.
• Existing catalysts often struggle with industrial conditions and facile preparation methods.

Purpose of the Study:

• To develop a self-standing MoC-Mo2C catalytic electrode for efficient HER.
• To utilize a one-step electro-carbiding process with CO2 as feedstock.

Main Methods:

• One-step electro-carbiding of molybdenum using CO2.
• Fabrication of a self-standing MoC-Mo2C electrode.
• Electrochemical characterization in acidic and alkaline electrolytes.

Main Results:

• Achieved low overpotentials for HER at 500 mA cm-2 (256 mV acidic, 292 mV alkaline).
• Demonstrated long-term stability (>2400 h) and high-temperature performance (70 °C).
• Identified key structural features: hydrophilic porous surface, heterojunctions, and favorable energetics for H* adsorption and water dissociation.

Conclusions:

• The MoC-Mo2C electrode offers outstanding HER performance and stability.
• The facile, scalable synthesis method using CO2 presents a promising pathway for industrial water electrolysis.
• The unique heterojunction structure is crucial for the catalyst's enhanced activity.