Hydrophobic TaO_x Species Overlayer Tuning Light-Driven Methane Chlorination with Inorganic Chlorine

Area of Science:

• Materials Science
• Catalysis
• Green Chemistry

Background:

• Halogenated methanes are key building blocks for high-value chemicals.
• Photocatalytic methane chlorination using sodium chloride offers an eco-friendly conversion route.
• Existing methods suffer from low efficiency and selectivity due to competing reactions in gas-solid-liquid systems.

Purpose of the Study:

• To enhance the efficiency and selectivity of photocatalytic methane chlorination.
• To develop a novel photocatalyst for methane conversion.
• To investigate the role of surface hydrophobicity in photocatalysis.

Main Methods:

• Fabrication of a hydrophobic TaOx layer on NaTaO3 via an in situ method.
• Characterization using in-situ XPS and XANES to analyze surface species.
• Evaluation of photocatalytic activity and selectivity in methane chlorination.

Main Results:

• The TaOx/NaTaO3 photocatalyst exhibited enhanced hydrophobicity, improving CH4 adsorption and activation.
• The optimized catalyst achieved a CH3Cl production rate of 233 µmol g⁻¹ h⁻¹ with 83% selectivity.
• Pure NaTaO3 showed negligible activity for CH3Cl formation and promoted CO2 production.

Conclusions:

• Surface modification with hydrophobic TaOx species effectively suppresses competing reactions in photocatalytic methane chlorination.
• The TaOx/NaTaO3 photocatalyst demonstrates superior performance and durability compared to noble metal catalysts.
• This strategy offers a promising approach for selective methane functionalization using inorganic chlorine ions.