Biomass-derived nitrogen-doped porous carbon with superior capacitive performance and high CO2 capture capacity

Superior Multifunctional Activity of Nanoporous Carbons with Widely Tunable Porosity: Enhanced Storage Capacities for Carbon‐Dioxide, Hydrogen, Water, and Electric Charge

“…As per comparative data represented in Figure i, the UMC450 (with SSA BET of 1620 m 2 g −1 ) exhibits equally good rate performance. Here, it is worth mentioning that even though ultramicroporous carbons have been reported in the literature their porosities and capacities are inferior to our UMCs . For instance, those ultramicroporous carbons, prepared under KOH activation, with nitrogen doping show CO 2 and EDLC values of 6.0–7.2 mmol g −1 and 140–310 F g −1 , which are lower than the capacities observed in our UMCs (Table , and Tables S1 and S3 in Supporting Information) .…”

“…PMCs/CMCs also show excellent rate performance through their capacitance retention with respect to the increased current loads. As per comparative data represented in Figure k, these samples with SSA BET of ≈2500 m 2 g −1 exhibit equally good rate and capacity performance with respect to the large number of samples reported in the literature . For example, micro‐/mesoporous graphitic carbon, with SSA BET of over 4000 m 2 g −1 , shows a capacitance value of just 225 F g −1 (and C SSA of 5.5 µF cm −2 ) at 0.5 A g −1 , far less than 320 or 270 F g −1 for the PMC450 or UMC450 with SSA BET of 2500 or 1620 m 2 g −1 .…”

“…The aqueous EDLC capacities between 300–320 F g −1 at 500 mA g −1 in our PMCs/CMCs with specific porosity characteristics outperform many of the other high surface area carbons (Figures g and f, and Figures S9 and 10 and Table S1 in Supporting Information) . This clearly indicates that most of the samples with ultrahigh porosity, for example, the samples with SSA BET greater than 2500 m 2 g −1 show reduced tendency in their EDLC values, and associated areal capacities are lower than 10 µF cm −2 (Figure h).…”

“…Interestingly, all the adsorptive capacities for EDCL, CO 2 , H 2 and H 2 O vary in a similar manner, linearly with respect to the SSA BET or pore volume (Figures and g). Here it is interesting to note that with respect to the SSA BET the UMCs show relatively high gravimetric as well as areal (surface area normalized capacitance, C SSA ) EDLC capacity when compared to numerous other high surface area carbons in the literature (Figure g–i) . The EDLC capacities (deduced at current loads of 0.5–1.0 A g −1 ) of the high surface area carbons from literature are summarily presented in Figure g (Table and Table S1 in Supporting Information).…”

“…Specifically, at a low CO 2 partial pressure of 0.15 bar, as a standard concentration in the postcombustion flue‐gas, the samples with ultranarrow pores show high CO 2 capture capacity, reaching to 2.75 mmol g −1 (≈12.1 wt%). The maximum capacity of 7.9 mmol g −1 (≈34.6 wt%) at 1 bar is also one of the highest values reported so far in the wide range of porous solids, including N‐doped activated carbons (ACs), MOFs (of open‐metal centers, micropores and flexible frameworks), microporous polymers, and solid‐amines . Uptake values deduced at 273 K and 1 bar in such different categories of materials family with respect to their SSA BET are comparatively summarized in Figure g.…”