Synthesis of ordered mesoporous carbons with channel structure from an organic–organic nanocomposite

Abstract

Mesoporous carbons with ordered channel structure (COU-1) have been successfully fabricated via a direct carbonization of an organic-organic nanocomposite.The discovery of nanostructured carbon materials such as fullerenes 1 and carbon nanotubes 2 has led to a considerable interest in the development of various carbonaceous materials. In particular, porous carbonaceous materials have been attracting much attention because of their high surface areas, large pore volumes, chemical inertness and high mechanical stability. Porous carbons show promise in the fields of hydrogen-storage, catalysis and electrochemistry. Many researchers have reported control of such pore structures through the template method, using various inorganic porous materials such as alumina membranes, 3 zeolites, 4-6 siliceous opals 7 and silica xerogels. 8 Recently, various types of ordered mesoporous carbons (OMCs) have been generated via a multistep synthetic procedure, in which ordered mesoporous silicas (OMSs) are employed as hard templates. [9][10][11][12][13][14][15] The most common synthetic route yielding OMCs involves preparation of OMS templates, impregnation of the OMS pores with carbon precursors, carbonization, and removal of the templates ( Fig. 1(A)). The removal of the OMS templates can be performed through a treatment with HF solution, converting the carbon into a porous form, while retaining the nanostructural features of the OMSs.In contrast, our novel OMC synthesis route, reported here, avoids the use of hard templates, and could thus reduce the number of preparation steps and the cost involved in producing these materials. Our strategy is to use an organic-organic interaction between a thermosetting polymer and a thermallydecomposable surfactant to form a periodic ordered nanocomposite. The thermosetting polymer is carbonized by heating under N 2 , after which process it remains as a carbonaceous pore wall ( Fig. 1(B)). Resorcinol/formaldehyde (RF) and triethyl orthoacetate (EOA) were used as the carbon co-precursors and triblock copolymer Pluronic F127 was used as a surfactant (Fig. 1(C)). The resultant materials are referred to as COU-1.In a typical synthesis, 0.661 g resorcinol was completely dissolved in a mixture composed of 1.74 g deionized water, 2.3 g ethanol and 0.06 ml hydrochloric acid (5 mol l 21 ). Then, 0.378 g Pluronic F127 was added to the resorcinol solution. After the complete dissolution of the Pluronic F127, 0.487 g of triethyl orthoacetate and 0.541 g of formaldehyde was added to the solution, and stirred at 30 uC for 20 min. The resultant solution was added dropwise to a silicon substrate spinning at 50 rpm, and then the substrate was spun up to 1000 rpm for 2 min. For polymerization of the resorcinol with formaldehyde, the asdeposited sample was heated at 90 uC for 5 h, in air. Then, the resultant brown deposit was carbonized under a nitrogen atmosphere at 400 uC for 3 h at a heating rate of 1 uC min 21 , followed by further carbonization at 600 and 800 uC for 3 h.{ Electronic supplementary informati...

General Synthesis of Ordered Nonsiliceous Mesoporous Materials

“…Electron microscopy images of the carbon film are shown in Figure 9. Similar results were reported by Tanaka et al (84), in which the same carbon precursor and Pluronic F127 (E0 10 6P07oE0 10 6) were used for organic-organic self-assembly ( Figure 10). Triethyl orthoacetate (EOA) was added as a carbon co-precursor.…”

Recent progress in soft-templating of porous carbon materials

“…Tanaka et al demonstrated that the common and cheap Pluronic triblock-copolymer PEO-b-PPO-b-PEO can also template mesoporous carbon. 44 They employed Pluronic F127 as a template, resorcinol-formaldehyde ''RF'' as a carbon precursor, and triethyl orthoacetate (EOA) as a co-precursor. EOA served two purposes; it increased the carbon content of the final material and significantly enhanced the ordering of the porous structures.…”

Nanopores array of ordered mesoporous carbons determine Pt's activity towards alcohol electrooxidation

“…Along with the development of nanocarbon science, more and more novel nanostructured carbon materials have been adopted as new support materials, and have already shown much better loading effect because of their unique nanostructure. [3][4][5][6][7] Among the reported nanocarbon supports, ordered mesoporous carbons (OMCs) are especially impressive, and are attracting increasing scientific interests due to their unusual physical and chemical characteristics, such as ordered and tailored nanostructure, high surface area, large pore volume, narrow pore size distribution in the mesopore range, high controlled pore surface chemistry, good electrical conductivity and so on. [5][6][7][8][9][10][11] Joo et al have firstly reported that an OMC with a highly ordered hexagonal array of nanoporous carbons, CMK-5, supported a high dispersion of Pt nanoparticles (<3 nm), exceeding that of many common microporous carbon materials, which gave rise to a promising electrocatalytic activity for oxygen reduction reaction.…”

“…[3][4][5][6][7] Among the reported nanocarbon supports, ordered mesoporous carbons (OMCs) are especially impressive, and are attracting increasing scientific interests due to their unusual physical and chemical characteristics, such as ordered and tailored nanostructure, high surface area, large pore volume, narrow pore size distribution in the mesopore range, high controlled pore surface chemistry, good electrical conductivity and so on. [5][6][7][8][9][10][11] Joo et al have firstly reported that an OMC with a highly ordered hexagonal array of nanoporous carbons, CMK-5, supported a high dispersion of Pt nanoparticles (<3 nm), exceeding that of many common microporous carbon materials, which gave rise to a promising electrocatalytic activity for oxygen reduction reaction. 8 Calvillo et al have adopted a functionalized OMC with a highly ordered hexagonal array of carbon nanorods, CMK-3, to support Pt nanoparticles, and the as-prepared catalyst showed improved catalytic performance for methanol electrooxidation in comparison with Vulcan XC-72 carbon black.…”