Beyond the Selectivity-Capacity Trade-Off: Ultrathin Carbon Nanoplates with Easily Accessible Ultramicropores for High-Efficiency Propylene/Propane Separation

Abstract

Rapid and highly efficient C 3 H 6 /C 3 H 8 separation over porous carbons is seriously hindered by the trade-off effect between adsorption capacity and selectivity. Here, we report a new type of porous carbon nanoplate (CNP) featuring an ultrathin thickness of around 8 nm and easily accessible ultramicropores (approximately 5.0 Å). The ultrathin nature of the material allows a high accessibility of gas molecules into the interior transport channels, and ultramicropores magnify the difference in diffusion behavior between C 3 H 6 and C 3 H 8 molecules, together ensuring a remarkable C 3 H 6 / C 3 H 8 separation performance. The CNPs show a high and steady C 3 H 6 capacity of up to 3.03 mmol g −1 at 298 K during consecutive dynamic cycles, which is superior to that of the state-of-the-art porous carbons and even porous crystalline materials. In particular, the CNPs show a rapid gas diffusivity, which is 1000 times higher than that of conventional activated carbons. This research provides a promising design principle for addressing the selectivity-capacity trade-off for other types of adsorbent materials.

Probing sub-5 Ångstrom micropores in carbon for precise light olefin/paraffin separation

“…2 and 3, Supplementary Figs. [17][18][19][20][21][22], and the micropore volume can be directly calculated from the intercept (Eq. 4) 46 .…”

“…porosity, excellent stability, and low cost [17][18][19] . However, regarding the olefin/paraffin separation, the conventional equilibrium separation based on favorable enthalpic interaction toward olefins or paraffins cannot confer carbon materials with desirable selectivity due to their similar physicochemical properties 20 .…”

Hierarchically Nanoporous Carbon for CO2 Capture and Separation: Roles of Morphology, Porosity, and Surface Chemistry

“…21 and 43°, which, respectively, correspond to the (002) and (100) planes . Notably, the (002) diffraction peaks of NHPC- z samples gradually shift to a higher degree from 21.3° of NHPC-0.5 to 25.4° of NHPC-2.0 (Figure d), which should be related to their morphology and structure, reflecting the generation of high densely packed sheet structures …”

“…30 Notably, the (002) diffraction peaks of NHPC-z samples gradually shift to a higher degree from 21.3°of NHPC-0.5 to 25.4°of NHPC-2.0 (Figure 2d), which should be related to their morphology and structure, reflecting the generation of high densely packed sheet structures. 31 The graphitization degree or structural defects of the carbon skeleton were further analyzed by Raman spectroscopy (Figure 2e,f). Two peaks located at ca.…”

Precise Control of Ultramicropores of Novel Carbons Molecule Sieves Derived from Coffee Bean for Efficient Sieving Propylene from Propane

“…On the contrary, carbon materials inherently possess excellent stability and low manufacturing costs, while their amorphous structure usually results in low adsorption selectivity. Despite the challenging in amorphous structure, a series of novel powdery carbon molecule sieves for separation of C 3 H 6 and C 3 H 8 were reported recently. − For example, SCMS-0.2–800 exhibited superhigh C 3 H 6 /C 3 H 8 uptake ratio up to 64 at 298 K and 100 kPa. MOFs-derived carbon adsorbents showed a high C 3 H 6 /C 3 H 8 uptake ratio up to 15.2.…”