Mechanism, performance enhancement, and economic feasibility of CO2 microbial electrosynthesis systems: A data-driven analysis of research topics and trends

Microbial electrosynthesis (MES), a neoteric technology, has attracted much interest in recent ten years. This work conducts network analyses in the CO2 bio-reduction based on MES to reveal critical information and guidance on the reports published, the topical changes involved, and the areas deserving extra attention. The research progress can be divided into three stages with themes of exploring electron transfer mechanisms, enhancing MES performance, and improving MES economic feasibility, respectively. Sufficient understanding of extracellular electron transfer is the basis for enhancements of productivity and selectivity towards CO2 bioelectrosynthesis, and more tools are combined to explore the kinetics of electron transfer and expression of functional genes. The promotion of MES performance can be achieved by not only improving the configurations and structures of MES reactor itself but also integrating it with other units. Efficient strategies, like electrode modification, electron donor addition, CO2 supply mode shift, and imposed potential regulation, are demonstrated to boost the production of longer carbon chain carboxylates and corresponding alcohols. In the perspective of economic development and environmental sustainability, renewable surplus energy to bioelectrochemically converse the CO2 captured using negative emission technology is recommended for reducing carbon emissions. Moreover, specific aspects related to the mechanism, performance and application that are worthy of coverage in future researches are also elucidated. This review aims to provide references for researchers dedicated to effective CO2 abatement via MES.