Transport Mediating Core-Shell Photocatalyst Architecture for Selective Alkane Oxidation.

Area of Science:

• Materials Science
• Catalysis
• Photochemistry

Background:

• Direct conversion of methane to valuable oxygenates is challenging due to high C-H activation energy and overoxidation of products.
• Existing methods struggle with selectivity and yield, particularly under high UV intensity.

Purpose of the Study:

• To develop a novel photocatalyst for selective direct conversion of methane to oxygenates.
• To overcome the limitations of overoxidation and low selectivity in methane conversion.

Main Methods:

• Synthesis of a core-shell nanostructured photocatalyst: silica encapsulated TiO2 decorated with AuPd nanoparticles (TiO2@SiO2-AuPd).
• Photocatalytic conversion of methane and oxygen under varying pressures and UV intensities.
• Systematic investigation of the photocatalyst's working principles.

Main Results:

• The TiO2@SiO2-AuPd photocatalyst demonstrated high selectivity (94.5%) for oxygenates.
• Achieved a total oxygenate yield of 15.4 mmol/gcat·h at 9.65 bar CH4 and O2 pressure.
• Prevented methanol overoxidation, even at high UV intensity.
• The design concept proved generalizable for other alkane oxidations.

Conclusions:

• The core-shell nanostructured photocatalyst effectively enables selective direct conversion of methane to oxygenates.
• This approach offers a promising room-temperature solution for producing fuels and chemical feedstocks from methane.
• The developed photocatalyst design has broad applicability for selective alkane oxidation.