Nitrogen doped activated carbon derived from chitosan/hexamethylenetetramine: structural and CO2 adsorption properties

Abstract

Chitosan and chitosan/ hexamethylenetetramine (HMT) macrospheres were prepared respectively by dropping chitosan and chitosan/HMT (in wt/wt ratios of 1:1 and 1:3) solutions in aq. NaOH solution.Here, HMT served as an additional nitrogen precursor for in-situ N-doping with chitosan derived activated carbon (AC). The as-formed macrospheres were impregnated using ZnCl 2 , freeze-dried, and carbonized at 500°C under inert atmosphere to yield ACs of average size 2.6 mm. All the samples were characterized using SEM, EDS, CHNS Analyzer, TGA, FT-IR, Raman, XRD and BET surface area analyzer. All the samples showed mesoporous characteristics. The surface area of the AC without HMT, with 1:1 HMT, and 1:3 HMT were 391.502, 259.017, and 111.717 m 2 /g respectively. Similarly, the pore volumes of AC without HMT, with 1:1 HMT and 1:3 HMT were 0.138, 0.095 and 0.075 cc/g respectively. The chitosan/HMT derived AC possessed higher N-content and better thermal stability, however exhibited lower surface properties with increasing HMT content. Deterioration in adsorption capacity of chitosan/HMT derived AC may be attributed to the physical cross-linking of chitosan polymer chains induced by increase in pH with addition of HMT and also the intermolecular H-bonding interaction between HMT and chitosan, which in turn reduces the surface area of as-formed N-doped ACs progressively.

Recent developments in polysaccharide and lignin-based (nano)materials for CO2 capture

“…Malini and co-workers prepared N-doped porous AC using CS and hexamethylenetetramine (HMT) (in ratios of 1 : 1 and 1 : 3 wt/ wt) as the carbon precursor and an additional nitrogen source, respectively. 191 The CS/HMT-derived AC had a larger N-content and enhanced thermal stability, but as the HMT content increased, the surface characteristics decreased. At 25 °C, the CO 2 adsorption of AC produced from CS was determined to be 97.98 mg g −1 , compared to 72.95 and 55.11 mg g −1 for AC/ HMT (1 : 1) and AC/HMT (1 : 3), respectively.…”

Natural polymers as sustainable precursors for scalable production of N/SOx doped carbon material enabling high‐performance supercapacitors

“…38 On the other hand, chitosan from crab shells and shrimps is a well-known costeffective natural precursor with covalently attached amino functionalities to produce N-doped carbon materials. 39,40 Moreover, it was recently reported that covalently attached amine functionalities produce carbon materials with high nitrogen contents and a suitable hierarchical porous architecture. Nevertheless, these two natural materials have never been used together to synthesize organically induced N/SO x species in carbon materials.…”

“…In our previous work, the sulfonate groups in sulfonated lignin have been recognized as the sacrificial template to generate the oxygenated CSC moieties and increase the porous architecture of the carbon materials 38 . On the other hand, chitosan from crab shells and shrimps is a well‐known cost‐effective natural precursor with covalently attached amino functionalities to produce N‐doped carbon materials 39,40 . Moreover, it was recently reported that covalently attached amine functionalities produce carbon materials with high nitrogen contents and a suitable hierarchical porous architecture.…”

Chitosan-Derived Nitrogen-Doped Carbon as a Support of Cobalt(II)-Phthalocyanine/Gold Nanoparticles for Photocatalytic Water Splitting

“…Chitosan gained a broad range of applications due to the some special features such as ecofriendly nature, abundancy, low cost, easy manipulation, high content of nitrogen, and insolubility in most of the solvents . This biopolymer could be the fascinating precursor for the synthesis of nitrogen-doped carbon (NC) by a thermal decomposition reaction because it could provide both nitrogen and carbon atoms for the construction. − This facile, effective, and inexpensive pathway provides NC for various purposes, in particular, it generates an optically active support for the photocatalysts . The obtained NC has some characteristics such as strongly anchoring to the transition metals, high optical activity, generating n-type semiconductor, and sustainability. − This kind of semiconductor easily retards charge recombination due to the presence of nitrogen atoms, which leads to the durability of the photocatalyst .…”

“… 1 This biopolymer could be the fascinating precursor for the synthesis of nitrogen-doped carbon (NC) by a thermal decomposition reaction because it could provide both nitrogen and carbon atoms for the construction. 2 − 7 This facile, effective, and inexpensive pathway provides NC for various purposes, in particular, it generates an optically active support for the photocatalysts. 8 The obtained NC has some characteristics such as strongly anchoring to the transition metals, high optical activity, generating n-type semiconductor, and sustainability.…”