Distinct Pathways in Visible-Light Driven Thermo-Photo Catalytic Methane Conversion

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Direct photocatalytic methane conversion using visible light is a significant scientific challenge.
• Developing efficient and selective catalysts for methane conversion is crucial for energy applications.

Purpose of the Study:

• To develop a highly efficient visible-light driven methane conversion process.
• To investigate the mechanism of oxygenate production and CO2 evolution.
• To guide the design of advanced visible-light driven methane conversion systems.

Main Methods:

• Development of a visible-light-responsive Pt/WO3 catalyst.
• Implementation of a thermo-photocatalytic process combining heat and visible light.
• Analysis of liquid oxygenate production (e.g., methanol) and CO2 evolution.
• Use of solid isotope evidence to elucidate reaction pathways.

Main Results:

• Achieved highly efficient visible-light driven methane conversion for the first time.
• Conversion efficiency was 4.6x higher than room-temperature photocatalysis and 14.7x higher than thermal catalysis at 150 °C.
• Demonstrated high apparent quantum efficiencies for liquid oxygenate production (e.g., 5.9% at 350 nm).
• Confirmed parallel reaction pathways for methanol, formaldehyde, and CO2 production via isotope studies.

Conclusions:

• The developed thermo-photocatalytic process significantly enhances visible-light driven methane conversion efficiency.
• Methanol production occurs via photocatalysis, while CO2 evolution is photoassisted thermal catalysis.
• Parallel reaction pathways are confirmed, offering insights into controlling selectivity for methane conversion.