Enhanced Multi-Carbon Selectivity Via Tandem CO2 Electroreduction

Electrifying chemical production is a potential approach to decarbonizing the chemical industry. Currently, 21% of the global greenhouse gas emissions come from the industry sector, while chemical manufacturing accounts for the largest share of industrial carbon emissions 1 . The electrochemical processes, when powered by renewable electricity, have lower carbon footprints than conventional thermochemical routes. The rapid development of renewable energy provides opportunities for electrifying chemical production and decarbonizing the chemical industry. Among these, electrochemical CO 2 reduction reaction (CO 2 RR) attracted much attention as a potential pathway for carbon utilization and sustainable chemical production. In this presentation, I would like to present a tandem CO 2 electroreduction scheme for multicarbon production. A molecular tuning strategy is applied to tune the intermediate binding energy and thus enhance the CO selectivity in the first step 2 . Then CO 2 and CO electroreduction to C 2+ products in alkaline conditions are compared, with particular emphasis on carbonate formation and carbon efficiency (i.e., the amount of carbon ended in the desired products divided by the total amount of CO 2 consumed) 3 . The conclusion is that CORR shows specific advantages over CO 2 RR in the aspects of C 2+ selectivity, stability, carbon efficiency, and single-pass conversion. Then oxide-derived Cu plates are chosen for the second step in tandem reduction, which shows a C 2+ Faradaic efficiency of 83% at -0.59 V vs RHE. Lastly, we further extend our tandem system to electrocatalytic–thermocatalytic reaction for CO 2 conversion to C 3 oxygenate 4 . A 25 cm 2 membrane electrode assembly device is coupled with a thermochemical hydroformylation reactor to produce 1-propanol and propanal. A total C 3 oxygenate selectivity of ~18% is achieved in the tandem reaction. References: Xia, R.; Overa, S.; Jiao, F., Emerging Electrochemical Processes to Decarbonize the Chemical Industry. JACS Au 2022, 2 (5), 1054-1070. Xia, R.; Zhang, S.; Ma, X.; Jiao, F., Surface-functionalized palladium catalysts for electrochemical CO 2 J. Mater . Chem. A 2020, 8 (31), 15884-15890. Xia, R.; Lv, J.; Ma X.; Jiao, F., Enhanced multi-carbon selectivity via CO electroreduction approach. Catal. 2021, 398, 185-191. Biswas, A. N.; Xie, Z.; Xia, R.; Overa, S.; Jiao, F.; Chen, J. G., Tandem Electrocatalytic–Thermocatalytic Reaction Scheme for CO 2 Conversion to C 3 ACS Energy Letters 2022, 2904-2910.