A sustainable strategy to reduce net methane emissions from thermokarst lakes by electrochemical methane partial oxidation

Global warming increases methane emissions from Arctic permafrost, which in turn reaccelerates global warming, creating a vicious cycle. Addressing this issue requires innovative solutions, such as electro-assisted methane partial oxidation (EMPO), which can provide an on-site facility for sustainable methane emission reduction in permafrost. In this study, a Co singe-atom catalyst was synthesized as an oxygen reduction reaction (ORR) catalyst that can be practically applied to stand-alone EMPO systems. To address performance degradation and cold weather freezing due to flooding of the electrodes, the hydrophobic polytetrafluoroethylene was mixed into a catalyst layer to regulate the microenvironment near cathodes. Furthermore, hydrophobic cathodes offer a pathway for nonpolar gases to increase the local concentration of methane. The enhanced local methane concentration, combined with an efficient ORR catalyst, yields 8 mmol g cat 1 formic acid at a low potential bias. Remarkably, the EMPO system exhibits a consistent production even with air and is highly stable. This leads to possibility of on-site facility for methane conversion without external energy at thermokarst lakes. A sustainable strategy to reduce methane with stand-alone facility is described. This study suggests a sustainable stand-alone facility to convert methane gas into a value-added chemical source at permafrost by enhancing the local concentration of methane controlled by hydrophobicity of the catalyst layer. This strategy can be used to remove methane from thermokarst lakes, thereby solving pond ecosystem and soil pollution. • Solving pond ecosystems by removing CH 4 from thermokarst lakes. • Arctic permafrost emissions CH 4 removal using electro-assisted methane partial oxidation (EMPO). • Partial oxidation of methane to produce 8 mmol g cat –1 formic acid. • Demonstration of solar-powered EMPO system without external energy supply.