A review on electrochemical CO2-to-CH4 conversion for a sustainable energy future: From electrocatalysts to electrolyzers

Abstract

The electrochemical reduction of carbon dioxide (CO2) to methane (CH4) is rapidly emerging as a promising strategy to produce renewable fuels while enabling carbon circularity. Fundamental research has uncovered promising electrocatalysts and mechanistic insights, however translating these advances into scalable industrial solution remains a major challenge. This review addresses this critical gap by providing a comprehensive and focused overview of the electrochemical CO2-to-CH4 conversion, from fundamental reaction mechanisms to system-level implementation. This work systematically analyzes the most selective and active electrocatalysts developed to date, elucidating key design principle that govern CH4 production. In addition, we assess the evolution of CO2 electrolyzers tailored for CH4, comparing device configurations, operational strategies, and levels of technological maturity. Techno-economic evaluations are also integrated to identify bottlenecks and realistic near-term implementation scenarios. As demand for green CH4 rises at a pace that outstrips conventional CH4 growth, this technology emerges as a timely solution to decarbonize hard-to-abate sectors using renewable electricity.