H2S-mediated thermal and photochemical methane activation

Area of Science:

• Chemical Engineering
• Photochemistry
• Catalysis

Background:

• Sustainable energy and feedstock production requires efficient natural gas activation.
• Sub-quality (
• sour
• ) natural gas, rich in hydrogen sulfide (H2S), is currently uneconomical to process.
• Conventional methods for natural gas activation are often energy-intensive and not CO2 neutral.

Purpose of the Study:

• To develop a sustainable, low-temperature method for activating sour natural gas.
• To investigate the H2S-mediated methane activation pathway via direct photolysis.
• To explore the potential for producing valuable hydrocarbon intermediates and hydrogen fuel.

Main Methods:

• Direct photolysis of sub-quality natural gas (methane and H2S mixture).
• Investigation of the CH4 + H2S complex under photoexcitation.
• Analysis of reaction pathways involving conical intersections and barrierless relaxation.

Main Results:

• Photoexcitation of H2S in the CH4 + H2S complex leads to the formation of methanethiol (CH3SH) and hydrogen (H2).
• The reaction proceeds via a barrierless relaxation through a conical intersection.
• The produced CH3SH can be further processed into higher hydrocarbons over acidic catalysts, and H2 can be utilized as fuel.

Conclusions:

• H2S-mediated methane activation via photolysis offers a sustainable, low-temperature route for sour gas utilization.
• This photolytic process is CO2 neutral, contrasting with conventional steam methane reforming (SMR).
• The method provides enhanced control and efficiency compared to existing industrial processes.