Self‐Pillared Ultramicroporous Carbon Nanoplates for Selective Separation of CH₄/N₂

Abstract

There is growing evidence that pillaring up a densely packed ultramicroporous two‐dimensional (2D) structure is an effective strategy to reduce their internal diffusion. Reliable pillaring paradigms, however, is rather challenging. Here we report a one‐pot multi‐component sequential assembly method for the preparation of a new self‐pillared 2D polymer and ultramicroporous carbon with integrated surface protrusions. The molecular level pillaring process is surprisingly fast, that is, in 10 min. The thickness of nanoplate edge and the density (roughness), angle as well as height of protrusions can be precisely tuned. Exemplified in coal bed methane purification/separation, this unique pillared 2D carbons exhibit a CH4/N2 selectivity up to 24 at a low CH4 partial pressure and two orders of magnitude faster CH4 diffusion kinetics than the commercial carbon molecular sieves. This solution synthesis methodology is generalizable for creation and fine tuning of pillared 2D heterostructures.

Improving CH4 uptake and CH4/N2 separation in pillar‐layered metal–organic frameworks using a regulating strategy of interlayer channels

“…In addition, using a short, thin pillar (PIZ), the obtained structures had a small pore size that constrains gas adsorption as well as a moderate specific surface area. Therefore, Ni(BTC)(PIZ) exhibited the highest CH 4 adsorption capacity of 1.62 mmol/g at 1 bar, which was better than that of most typical porous materials such as Cr‐MOF‐101 (0.26 mmol/g), 27 Cu‐BTC (0.91 mmol/g), 31 PCNPS (1.17 mmol/g), 41 and TUT‐100 (1.25 mmol/g) 42 . On the other hand, the modulation of pillars on the three structures also affected the adsorption of N 2 , the order of their adsorption amount is consistent with the adsorption of CH 4 .…”

A Stable Cu(I)-Based Ultramicroporous NKMOF-8-Br with High CH4 Uptake for Efficient Separation of CH4/N2 Mixtures

“…At 298 K and 1.0 bar, it is 1.84 mmol/g for CH 4 and 0.36 mmol/g for N 2 . To our best knowledge, the CH 4 adsorption capacity exceeds those of all zeolites, carbon materials and water stable MOFs used in CH 4 /N 2 separation (Figure b), such as ZK-5 (0.82 mmol/g), pillared carbon nanoplates (PCNPs) (1.17 mmol/g), Co 3 (C 4 O 4 ) 2 (OH) 2 (0.40 mmol/g), Al-CDC (1.43 mmol/g), STAM-1 (0.63 mmol/g), ZIF-94 (1.51 mmol/g), Ni-MA-BPY (1.0 mmol/g), and CAU-21-BPDC (0.99 mmol/g), zeolite 5A (1.0 mmol/g), and NaY (1.01 mmol/g) . To demonstrate the reproducibility of the sample, two batches of samples have been synthesized and tested for CH 4 and N 2 adsorption isotherms, as shown in Figure S11.…”

Recent Advances in Carbon-Based Adsorbents for Adsorptive Separation of Light Hydrocarbons

“…To overcome the diffusion limitations, the conventional strategy is to build a hierarchical pore system by imparting meso/ macropores. However, Lu and co-workers show a distinct and effective method by pillaring up the 2D ultramicroporous carbons nanoplates (PCNPs) through highly processible synthesis [77]. The pillared polymer nanoplates are based on a multicomponent sequential assembly, in which the protrusions were in situ grown on the soft 2D templates (selfassembly of triblock copolymers and stearic acid) by inducing sequential condensation of phloroglucinol, terephthalaldehyde, and p-phenylenediamine (p-PDA).…”