Recoverable operation strategy for selective and stable electrochemical carbon dioxide reduction to methane

In the carbon dioxide (CO2) electroreduction reaction, catalysts determine, to a large extent, the system’s product selectivity, energy efficiency and stability. Conventionally, catalysts are prepared and optimized ex situ before the reaction, but they often suffer from low stability due to intrinsic structural changes during the reaction. Here we demonstrate a recoverable operation strategy for selective and stable electroreduction of CO2 to methane. In this approach, active catalysts are formed and fully reset in situ during CO2 electroreduction reaction. By stabilizing catalyst precursors and controlling the formation and removal of the catalysts, we demonstrate an over 500-hour CO2-to-methane conversion with a Faradaic efficiency of over 60% at the reduction current density of above 0.2 A cm−2 and full-cell voltage of below 4.0 V. We further showcase benefits of the recoverable operation for potential integration with intermittent renewable power supply, contributing to more than 100 days with day-on and night-off operation.