Atomic engineering of Cu-N coordination sites for high-performance CO2-to-CH4 electroreduction

Electrocatalytic CO 2 methanation is promising for carbon neutrality but hindered by complex multi-electron transfer process, thereby obtaining low product selectivity. Herein, we report a copper single atom catalyst anchored on nitrogen doped carbon nanotubes (Cu-N-CNTs) for efficient electrocatalytic CO 2 methanation. By synergistically regulating the precursor, Cu-N 4 active sites are precisely constructed at the atomic scale, effectively suppressing copper aggregation. In situ characterization indicates that the catalyst forms a moderate local alkaline microenvironment during the reaction, suppressing C-C coupling side reactions and promoting methane pathways. In the flow cell, Cu-N-CNTs achieve a FE CH4 of 59.2% and a partial current density of 168.7 mA cm −2 at −1.577 V vs. RHE, and operated stably for 10 h. Moreover, Cu-N-CNTs exhibit remarkable methane selectivity in membrane-electrode assembly (MEA) systems employing both alkaline and pure-water electrolytes. A scaled-up MEA prototype further verifies the outstanding operational stability of Cu-N-CNTs under practical conditions. These results collectively underscore the substantial potential of Cu-N-CNTs for industrially relevant electrocatalytic CO 2 methanation.