Electrochemically mediated CO2 reduction for bio-methane production: a review

A number of methods for carbon capture, more specifically, CO2 capture have been researched in the past few years. One such method is electrochemical CO2 reduction to biomethane which also serves the purpose of biogas upgradation using microbial electrosynthesis systems. This technology is also known as Power to Gas technology and the review starts with the importance and requirement of PtG in the modern world by studying energy production and consumption patterns in Europe, with a focus on Norway. The paper summarises the recent works and concepts in the field of bioelectrochemical systems with a focus on electron transfer mechanisms, biocatalysts and reactor designs. Works and gaps in the studies of direct interspecies electron transfer and biocathode developments are discussed in detail. This is followed by a discussion explaining various reactor designs, the advantages of single chambered microbial reactors and the importance of reactors that combine anaerobic digestion with microbial electrolysis cells.