Progress and Perspective of Direct Utilization of Flue Gas for Electrochemical CO2 Reduction.

Electrochemical carbon dioxide reduction reaction (CO2RR) can convert CO2 into high-value chemicals and fuels, which not only offers a promising way to store the intermittent renewable electricity but also contributes to achieving carbon neutrality. Nevertheless, present-day CO2RR mainly relies on the use of high-purity CO2 as the feedstock, while sourcing CO2 from industrial flue gas requires additional costs for carbon capture and purification. Direct utilization of flue gas as feed for CO2RR presents a highly impressive perspective but is hampered by substantial barriers. In this review, we first elucidate the key challenges of direct flue gas conversion, including the complex gas composition, impurity poisoning effects, and critical carbon loss in neutral/alkaline electrolytes. Advanced catalyst design strategies that are aimed specifically at enhancing the conversion efficiency under low CO2 concentration, suppressing the competitive oxygen reduction reaction, and alleviating the SOX/NOX interference are then presented. Moreover, innovative routes for the co-electrolysis of CO2 with impurity gases are also discussed. This review is ended by elaborating on the forward-looking perspectives and key development directions in this exciting research field.