What matters in the emerging application of CO2 electrolysis

Renewable electricity triggered electrochemical conversion of CO2 and H2O into chemicals has gained substantial attention. The development of CO2 reduction reaction (CO2RR) electrolyzers is at an early stage. Undesirable voltage losses in CO2 electrolyzers limit the electrical energy efficiency below the cost-competitive target. The future development of the CO2RR technique towards economic viability requires a decreased cell voltage and a further improvement in Faradaic efficiency. This review systematically discusses these two determinative factors, with significant advances, and the remaining challenges for improving electrical energy efficiency.