Electro-conversion of carbon dioxide (CO2) to low-carbon methane by bioelectromethanogenesis process in microbial electrolysis cells: The current status and future perspective.

Graphical abstract Highlights • Current status of MECs for CO 2 electromethanogenesis was summarized. • The working principles of CO 2 electromethanogenesis were summarized. • Several test methods was proposed to analyze the properties. • The critical factors effecting CH 4 production have been discussed. Abstract Given the aggravated greenhouse effect caused by CO 2 and the current energy shortage, CO 2 capture and reuse has been gaining ever-increasing concerns. Microbial Electrolysis Cells (MECs) has been considered to be a promising alternative to recycle CO 2 bioelectrochemically to low-carbon electrofuels such as CH 4 by combining electroactive microorganisms with electrochemical stimulation, enabling both CO 2 fixation and energy recovery. In spite of the numerous efforts dedicated in this field in recent years, there are still many problems that hinder CO 2 bioelectroconversion technique from the scaling-up and potential industrialization. This review comprehensively summarized the working principles, extracellular electron transfers behaviors, and the critical factors limiting the wide-spread utilization of CO 2 electromethanogenesis. Various characterization and electrochemical testing methods for helping to uncover the underlying mechanisms in CO 2 electromethanogenesis have been introduced. In addition, future research needs for pushing forward the development of MECs technology in real-world CO 2 fixation and recycling were elaborated. [ABSTRACT FROM AUTHOR]