Abiotic Methane Production Driven by Ubiquitous Non-Fenton-Type Reactive Oxygen Species

Area of Science:

• Environmental Chemistry
• Geochemistry
• Photocatalysis

Background:

• Abiotic methane (CH4) production via Fenton-type reactive oxygen species (ROS) is a known contributor to the atmospheric CH4 budget.
• The potential for non-Fenton-type ROS to drive abiotic CH4 production remained unexplored.
• Natural geobattery materials and methyl donors are ubiquitous in environments where ROS are generated.

Purpose of the Study:

• To demonstrate and elucidate the mechanism of abiotic CH4 production driven by non-Fenton-type ROS.
• To investigate the role of polymeric carbon nitrides (CNx) and dimethyl sulfoxide (DMSO) in this process.
• To explore the applicability of this abiotic CH4 production pathway in various catalytic systems.

Main Methods:

• Photocatalytic experiments using polymeric carbon nitrides (CNx) to generate ROS.
• Oxidation of dimethyl sulfoxide (DMSO) as a methyl donor in the presence of ROS.
• Analysis of CH4 production and selectivity using gas chromatography.
• Expansion of the process to electrocatalysis, pyrocatalysis, and sonocatalysis.

Main Results:

• Demonstrated abiotic CH4 production at the soil-water interface under illumination.
• Photocatalytically produced ROS by CNx oxidized DMSO to CH4 with 91.5% selectivity.
• The abiotic CH4 production mechanism was successfully applied to electrocatalysis, pyrocatalysis, and sonocatalysis.

Conclusions:

• Non-Fenton-type ROS can effectively drive abiotic CH4 production from natural methyl donors.
• This study provides crucial insights into the geochemical cycle of abiotic CH4.
• Offers a novel pathway for CH4 production integrated with energy development.