Salt Templating with Pore Padding: Hierarchical Pore Tailoring towards Functionalised Porous Carbons

Abstract

We propose a new synthetic route towards nanoporous functional carbon materials based on salt templating with pore-padding approach (STPP). STPP relies on the use of a pore-padding agent that undergoes an initial polymerisation/ condensation process prior to the formation of a solid carbon framework. The pore-padding agent allows tailoring hierarchically the pore-size distribution and controlling the amount of heteroatom (nitrogen in this case) functionalities as well as the type of nitrogen (graphitic, pyridinic, oxides of nitrogen) incorporated within the carbon framework in a single-step-process. Our newly developed STPP method offers a unique pathway and new design principle to create simultaneously high surface area, microporosity, functionality and pore hierarchy. The functional carbon materials produced by STPP showed a remarkable CO /N selectivity. At 273 K, a carbon with only micropores offered an exceptionally high CO adsorption capacity whereas a carbon with only mesopores showed promising CO -philicity with high CO /N selectivity in the range of 46-60 %, making them excellent candidates for CO capture from flue gas or for CO storage.

Waste wool derived nitrogen-doped hierarchical porous carbon for selective CO2 capture

“…The salt concentration (such as the KOH amount used in activation) can alter the shape of the adsorption-desorption isotherm, and thus alter the specic surface area and especially the pore-size distribution of the activated carbon materials. [36][37][38] As can be seen from Fig. 5a, the un-activated sample WNPC has a very low nitrogen adsorption in the low pressure range and does not display a hysteresis loop in the middle pressure range, which reveals that only a small number of micropores exist in the WNPC.…”

“…In addition, we further used ideal adsorbed solution theory (IAST) [65][66][67][68] to predict CO 2 /N 2 selectivity in binary gas mixtures using only pure gas isotherms measured at 25 C. In the calculations, the ratio of CO 2 /N 2 is assumed to be 15/85, which is a typical component of ue gas. 6,37,66,67,69 Herein, the dual-site Langmuir model (DL) and the single-site Langmuir model (L) were chosen to t the CO 2 and N 2 adsorption isotherms, respectively, and then DL/L-IAST was utilized to estimate the CO 2 /N 2 selectivity of WNPC-3 ( Fig. S3 †).…”

“…[29][30][31][32] In addition, biomass precursors naturally contain some useful heteroatoms such as nitrogen that will be anchored on the surface of the carbon framework, and this will enhance the CO 2 adsorption capability of the carbon materials. [32][33][34] Meanwhile, chemical activation with KOH is found to be a very common and useful method for the preparation of porous carbon materials, [35][36][37] especially biomassderived porous carbon materials. [30][31][32][33][34]38 For instance, by means of KOH activation, Guo et al 38 successfully transformed waste coffee grounds into an effective porous carbon sorbent material for CO 2 capture.…”

Characterization of the adsorption site energies and heterogeneous surfaces of porous materials

“…Depending on the bulk pressure at which these sites host the target molecules, the adsorbent sites can be titrated with the host molecule and the surface properties can be characterized (see Section 2). Biomass derived carbons and many porous amorphous carbons that seem to contain a wide range of pore-size distributions with different types of functionalities like N, -OH, -COOH groups, together with the presence of any impurities, 52 can ultimately possess characteristic properties of a random and heterogeneous surface. Even porous polymers can fit under this category depending on the distribution of pore-size and pore-volume and presence of functionalities, if any.…”

Ultra‐Stable and High‐Cobalt‐Loaded Cobalt@Ordered Mesoporous Carbon Catalysts: All‐in‐One Deoxygenation of Ketone into Alkylbenzene

“…In general, the construction of metal@OMC catalysts includes the hard‐ or soft‐templating synthesis of OMCs, impregnation or precipitation of metal salts into OMCs, and reduction of the metal precursors . However, these complicated approaches still have several drawbacks such as a reliance on corrosive reagents (e.g., HF, NH 4 HF 2 ), the use of carcinogenic and fossil‐based precursors (e.g., formaldehyde, phenol, resorcinol), and the time (1–3 days) and organic solvent (e.g., ethanol, THF) consuming process for films/membranes . To date, the development of a facile and direct method to construct a Co@OMC catalyst with a high loading of stable Co NPs is highly challenging.…”