Self-Supported α-MoB/β-MoB₂ Ceramic Electrodes for Efficient High-Current-Density Hydrogen Evolution in Acidic,...

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Industrial electrocatalytic water splitting requires efficient and stable hydrogen evolution reaction (HER) catalysts.
• Developing catalysts that perform effectively across the entire pH range (acidic, neutral, and alkaline) is crucial for practical applications.

Purpose of the Study:

• To produce and evaluate self-supported α-MoB/β-MoB₂ ceramic electrodes for high-current-density HER.
• To investigate the HER performance of these electrodes in acidic, neutral, and alkaline media.
• To understand the role of α-MoB/β-MoB₂ heterojunctions in enhancing catalytic activity.

Main Methods:

• Tape-casting and phase-inversion processes followed by sintering to synthesize self-supported β-MoB₂ electrodes.
• In situ formation of α-MoB/β-MoB₂ heterojunctions through reaction with MoO₃.
• Electrochemical testing to measure overpotential and stability at high current densities.
• Density Functional Theory (DFT) calculations to analyze electronic structure and reaction mechanisms.

Main Results:

• The synthesized electrodes exhibited a porous structure facilitating electrolyte access and gas release.
• The α-MoB/β-MoB₂ heterojunctions significantly improved electrocatalytic performance.
• Achieved low overpotentials at 1000 mA·cm^-2 (289 mV in acid, 294 mV in base) and stable operation (>100 h).
• Demonstrated good performance in neutral solution (354 mV at 100 mA·cm^-2).

Conclusions:

• The self-supported α-MoB/β-MoB₂ ceramic electrodes show promising potential for industrial electrocatalytic water splitting due to their high HER activity and stability across all pH values.
• The heterojunction structure enhances electron transfer and facilitates hydrogen adsorption/water dissociation, crucial for efficient water splitting.