Mo-Doped Mesoporous RuO₂ Spheres as High-Performance Acidic Oxygen Evolution Reaction Electrocatalyst

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Developing efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing water electrolysis.
• Ruthenium dioxide (RuO2) is a key material, but its stability and efficiency in acidic conditions need improvement.

Purpose of the Study:

• To fabricate a highly active and acid-stable electrocatalyst for OER.
• To investigate the effect of molybdenum (Mo) doping on the properties of mesoporous ruthenium dioxide spheres.

Main Methods:

• A facile impregnation and post-calcination method was employed using mesoporous carbon spheres as templates.
• Molybdenum was doped into the ruthenium dioxide structure to create Mo-RuO2 catalysts.
• Electrochemical performance was evaluated using techniques like overpotential and Tafel slope measurements.

Main Results:

• The optimal Mo0.15-RuO2 catalyst (15 mol.% Mo doping) showed a low overpotential (147 mV at 10 mA cm-2) and a small Tafel slope (38 mV dec-1).
• The catalyst exhibited enhanced electrochemical stability in acidic electrolytes compared to commercial RuO2.
• Characterization revealed a large surface area and robust mesoporous structure.

Conclusions:

• Molybdenum doping significantly enhances the OER performance of mesoporous ruthenium dioxide.
• The improved activity is attributed to the mesoporous structure and modified electronic properties of Ru active sites.
• Mo-doped mesoporous RuO2 spheres are a promising candidate for efficient electrocatalytic OER in acidic media.