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

Abiotic CH₄ production driven by Fenton-type reactive oxygen species (ROS) has been confirmed to be an indispensable component of the atmospheric CH₄ budget. While the chemical reactions independent of Fenton chemistry to ROS are ubiquitous in nature, it remains unknown whether the produced ROS can drive abiotic CH₄ production. Here, we first demonstrated the abiotic CH₄ production at the soil-water interface under illumination. Leveraging this finding, polymeric carbon nitrides (CN_x) as a typical analogue of natural geobattery material and dimethyl sulfoxide (DMSO) as a natural methyl donor were used to unravel the underlying mechanisms. We revealed that the ROS, photocatalytically produced by CN_x, can oxidize DMSO into CH₄ with a high selectivity of 91.5 %. Such an abiotic CH₄ production process was further expanded to various non-Fenton-type reaction systems, such as electrocatalysis, pyrocatalysis and sonocatalysis. This work provides insights into the geochemical cycle of abiotic CH₄, and offers a new route to CH₄ production via integrated energy development.