Recent advances in electrochemical carbon dioxide reduction strategies in biogas upgrading and biomethane production

• Recent research update on electrochemical biogas upgrading. • Electrochemical method for CO 2 to CH 4 synthesis is critically analyzed. • The novel catalyst and reactor developed were critically analyzed. Biogas upgrading technologies play a crucial role in purifying methane (CH 4 ), employing advanced processes to produce biomethane that meets natural gas grid-quality standards. Extensive research has been conducted on these technologies to maximize CH 4 content, the primary energy component in biogas, thereby enhancing its overall energy value and suitability for a variety of applications. This comprehensive review investigates emerging advances in electrochemical CO 2 reduction technologies, with a special emphasis on their application in converting biogas (CO 2 ) to biomethane. The study provides a critical analysis of the state of the art and potential future directions in this field, covering multiple aspects such as electrochemical reactors, catalyst development, electrode materials, operational conditions, understanding the mechanism and development of efficiency and selectivity, sustainability assessments, and upscaling possibilities. Further, the performance of this biogas upgrading strategy under various operating conditions, especially fed batch and continuous mode, in conjunction with the innovative cathode materials, has been thoroughly evaluated and reviewed. Gas diffusion electrodes, carbon-based nanotube or nanowire electrodes and continuous mode have demonstrated higher performance in supplying electrons for CO 2 to CH 4 reduction.