Initial CV experiments under CO2 showed changes consistent with the electrochemical capture of CO2 (Figure .1-S7.3). To quantify the electrochemical carbon capture performance of these materials, functionalized carbon samples were charged and then discharged under a CO2 atmosphere and the corresponding CO2 pressure changes were monitored (Figure ). As the cells were charged from -1 to -2 V, the grafted quinones were electrochemically reduced. This caused a decrease in the CO2 pressure as carbon dioxide was captured by reduced quinones. The material was then discharged causing the quinones to be oxidised. An increase in CO2 pressure was then observed due to the release of CO2. This is linked to the capture and release of CO2 and was observed in all three carbon samples qualitatively. The raw pressure data also showed a downwards slope linked to degradation present in the initial cycles. The magnitude of the capture and release slopes was analyzed to obtain the capture and release values shown in Figure CO2 adsorption values between the three carbon samples fell within the range of 0.2 to 0.6 mmol g -1 with f-YP-80F having the highest adsorption capacity (0.6 mmol g -1 ) followed by f-CMK-3 (0.4 mmol g -1 ) and f-BP-1300 (0.3 mmol g -1 ). Two theoretical adsorption capacities when either 1 or 2 eq. of CO2 is captured per quinone were calculated using the quinone loading values calculated from voltammetry above (Figure Across the carbon materials, different pore size distributions and anthraquinone environments have been shown to have a large effect on CO2 adsorption leading f-YP-80F to have the highest adsorption value despite a lower amount of electrochemically accessible quinones compared to f-CMK-3. The faradaic efficiency, the percentage of total charge extracted during cell discharge relative to during cell charging, for both f-YP-80F and f-CMK-3 was above 80% in the initial cycles however this still falls behind electrochemical capture systems reported in the literature, and suggests side reactions are taking place. f-BP-1300 showed a large difference between the electrochemical charge and discharge (Figure ), resulting in the lowest faradaic efficiency across the three materials (Figure ). This irreversibility was also seen in f-BP-1300 capture and release of CO2. Due to the suspected presence of irreversible processes in both electronic charge and CO2 capture values, electronic discharge and CO2 release values were used for analysis to accurately assess the reversibility of the systems and allow for an accurate comparison across the materials. Discharge: release percentage (Figure ) displays the ratio between the number of electrons flowing out of the material (discharge) compared to the number of CO2 molecules released (release), illustrating how many electrons were directly involved in CO2 capture over one cycle. f-YP-80F showed a high ratio of 55% for discharge: release indicating a large proportion of electrons stored in the material are directly used for carbon capture. For f-CMK-3 and f-BP-1300, the materials showed a high amount of electronic capacity (Figure ), however, the amount of adsorption capacity was low resulting in a discharge: release of <30% (Figure ). CV experiments under CO2 are shown to illustrate how the electrochemistry of the systems behave before and after extended cycling (Figure ). Overall electrochemical capacity retention was highest for f-YP-80F at 80.0% compared to f-CMK-3 and f-BP-1300 with 72.0% and 65.0%, respectively. f-BP-1300 showed substantial degradation leading to minimal adsorption capacity being recorded after 200 cycles. However, all three samples showed a decrease in current around -0.7 V due to the loss of faradaic contributions from the grafted anthraquinones. This indicates that cycling under CO2 causes anthraquinone to become unstable resulting in a loss of quinone molecules from the carbon surface.