Morphology and surface chemistry engineering toward pH-universal catalysts for hydrogen evolution at high current...

Area of Science:

• Electrochemistry
• Materials Science
• Catalysis

Background:

• Electrochemical hydrogen production requires efficient electrocatalysts.
• High current densities present challenges for existing catalysts.

Purpose of the Study:

• To develop inexpensive and efficient electrocatalysts for hydrogen evolution.
• To explore the impact of morphology and surface chemistry on catalyst performance.

Main Methods:

• Synthesized and tested three model electrocatalysts: platinum foil, molybdenum disulfide microspheres, and molybdenum carbide-modified molybdenum disulfide microspheres.
• Evaluated catalyst performance at high current densities (1000 mA cm⁻²).
• Analyzed catalyst activity across different pH levels.

Main Results:

• Molybdenum carbide-modified molybdenum disulfide microspheres exhibited high activity for hydrogen evolution.
• Achieved low overpotentials (227 mV in acidic, 220 mV in alkaline media) at 1000 mA cm⁻².
• Enhanced mass transfer and reaction kinetics were attributed to surface oxygen groups on molybdenum carbide.

Conclusions:

• Surface modification of molybdenum disulfide with molybdenum carbide creates highly active electrocatalysts.
• These catalysts demonstrate excellent performance independent of pH at high current densities.
• The findings provide guidance for designing advanced electrocatalysts for efficient hydrogen production.