Carbon-efficient carbon dioxide electrolysers

The electroreduction of CO 2 (CO 2 R) is the conversion of CO 2 to renewable fuels and feedstocks, a promising technology that could support the transition from fossil to renewable sources in the chemical industry. Today the viability of CO 2 R technology is limited by carbonate formation via the reaction of reactant CO 2 with hydroxides and the energy cost incurred to regenerate the reactant. In this Review, we analyse the literature on four emerging high single pass CO 2 conversion approaches: CO 2 regeneration from carbonate, CO 2 R in acidic media, cascade CO 2 R-COR and CO 2 R direct from a capture liquid. We analyse each system, describe the challenges associated with each pathway and outline future research directions towards the goal of ensuring that CO 2 R is viable and thus scalable.