Mechanistic Study of Energy Efficient Electrochemical Capture and Release of CO2 in Ionic Liquid Complexes
The work has been focused on using bipyridine and disulphide systems for electrochemical CO2 capture. In these systems, the electrogenerated nucleophiles i.e. bipyridinium radical anions (as shown in Figure 1) or thiolates reacts with CO2 to form an adduct. Furthermore, the CO2 adduct i.e. carbamate or thiocarbonate can be oxidized to release the precursor and CO2. The oxidation potential of these adducts shifts far positive as compared to the oxidation of the nucleophiles. Based on the detailed comparison of the experimental data with simulations using possible mechanistic models, it is found that the electrogeneration of nucleophiles reacts with CO2 to form an adduct and the direct oxidation of the adduct using EC mechanism releases the precursor and CO2.
We acknowledge the support from Advanced Research Projects Agency (ARPA-E) for this work.
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Figure-1 Experimental (black) and simulated (red) cyclic voltammograms for electrochemistry of 10 mM 4,4'-bipyridine in the presence of 10 mM CO2 in BMP+ TFSI- ionic liquid on glassy carbon electrode. Scan rate: 50 mV/s.