Ordered macroporous carbons

The present article first provided the brief overview of the synthetic methods of the porous carbons. In order to prepare the microporous carbons with high surface area, the physical/chemical activation methods have been widely used for a long time.18"35 Recently, the meso/macroporous carbons with various pore structures are prepared by templating methods by using various templates and changing sol-gel reaction conditions, e.g., pH, amount of template, and gelation temperature.17,36 55... 

In order to control the pore texture in carbon materials, blending of two kinds of carbon precursors, the one giving a relatively high carbonization yield and the other having a very low yield, was proposed and called polymer blend method [112], This idea gave certain success to prepare macroporous carbons from poly(urethane-imide) films prepared by blending poly(amide acid) and phenol-terminated polyurethane prepolymers [113]. By coupling this polymer blend method with... 

Kang S., Yu J. S., Kruk M. and Jaroniec M., Synthesis of an ordered macroporous carbon with 62 nm spherical pores that exhibit unique gas adsorption properties. Chem. Commun. (2002) pp. 1670-1671. 

Lai, C.-Z., Fierke, M.A., Stein, A., and Buhlmann, P. 2007. Ion-selective electrodes with three-dimensionally ordered macroporous carbon as the solid contact. Analytical Chemistry 79, 4621-1626. 

Fig. 4.11 Three-dimensionally ordered macroporous carbon by using monodispersed silica template and polyimide...

Fig. 4.13 Preparation process of three-dimensionally ordered macroporous carbon with controlled pore size distribution by using monodispersed polystyrene and silica beads...

Figure 4.15 shows the discharge and charge curves of the prepared three-dimensionally ordered macroporous carbon with controlled meso pores in Et NBPy PC at various currents. From the results, the electric capacity of this carbon was estimated to be 90 Fg . 

Carbonaceous materials such as porous carbons (e.g., active carbons and ordered nanoporous carbons) and nonporous carbons (e.g., carbon blacks) are a non-graphitic form of carbon characterized by internal surface areas ranging from lO-AO m g (nonporous or macroporous carbon blacks) to 500-3000 g" (active carbons). X-ray analysis shows that... 

Indeed, the past ten years have witnessed rapid advances in using template carbonisation to produce ordered porous carbon materials, ranging from microporous to mesoporous and macroporous carbons. The template carbonisation method has thus been regarded as one of the most effective approaches to prepare porous carbon materials with desirable physical and chemical properties. It has, therefore, opened up new opportunities in making novel porous materials for a wide range of applications. 

In principle, the morphology of macroporous carbon materials is largely dependent on the degree of void infiltration of the opal template. In order to maximise the filling of the interstitial voids of the colloid crystal with carbon precursors, liquid phase carbon precursors such as phenolic resin and sucrose solution are usually used to achieve better replication.1 2 -194] variety of carbon precursors, including propylene gas, benzene and divinylbenzene can also be successfully utilised to make three-dimensional macroporous carbon materials using colloid crystals as hard templates. The... 

The use of polymer microspheres as template has the advantage of eliminating the chemical dissolution step since the polymer template can simply wash away or burn off during the process. The use of polystyrene microspheres as template for the synthesis of ordered macroporous carbons was realised by Baumann and Satcher. Following infiltration of hydrogel into the interstitial spaces between polystyrene colloid spheres, the polystyrene sphere template was removed by washing with toluene, after which... 

Figure 4.16 SEM images of porous carbons prepared using hard template consisting of large polymer colloids (450 nm diameter) and small silica colloids. The particle size of silica colloids used as template for the small spherical pores is (a) 70-100 nm and (b) 40-50 nm. 1 Reprinted with permission from S.W. Woo, K. Dokko, K. Sasajima, T. Takei and K. Kanamura, Three-dimensionally ordered macroporous carbons having walls composed of hollow mesosized spheres. Chem. Commun., 4099—4101. Copyright (2006) Royal Society of Chemistry...

The Dubinin equation (Dubinin, 1966, 1967, 1972, 1975) has its history in the development of theory for adsorption in activated carbon. Activated carbon has a very complex structure (see Chapter 1 for some details), with pores ranging from macropores of order of greater than 1000 A to micropores of order of 10 A. It is this micropore network where most of the adsorption capacity resides. Because of the pore dimension comparable to the dimension of adsorbate molecule, the adsorption mechanism in micropore is completely different from that on a surface of a large pore, where adsorption occurs by a layering process. In micropores, the mechanism is due to micropore filling because of the adsorption force field encompassing the... 

Baumann T, Satcher J (2003) Homogeneous Incorporation of Metal Nanoparticles into Ordered Macroporous Carbons. Chem Mater 15 3745-3747. 

In this chapter, we provide an overview of the recent research and development in the preparation, characterization, and application of novel porous carbons using both the endotemplate and the exotemplate methods. A discussion of zeolite templates for microporous carbons is followed by that of ordered mesoporous silica templates for OMCs, nanoparticle templates for mesoporous carbons, sol-gel processed porous carbons, self-assembled colloidal crystal templates for ordered macroporous carbons, and colloidal sphere templates for hollow carbon spheres, as well as other templating approaches to preparing carbon nanostructures. Then,... 

The colloidal-crystal-templating approach offers yet another new approach to preparing 3-D macroporous solid materials [6,17]. Spherical colloidal particles of submicrometer size can self-organize themselves into a colloidal crystal, the so-called opal [64], which can be utilized as an endotemplate to fabricate ordered macroporous carbons of two types volume-templated carbon, which is an exact inverse replica of the opal template, and surface-templated carbon, which is formed by coating the colloidal spheres. Zakhidov et al. [64] were the first to use colloidal crystals as templates to prepare highly ordered 3-D macroporous carbon of both types. As schematically illustrated in Figure 2.39, for the volume-templat-ing approach, a carbon precursor is infiltrated into interstitial spaces between colloidal spheres. Carbonization and removal of the opal template leave behind a 3-D periodic carbon structure (i.e., an inverse carbon). With this approach, macroporous carbon structures with a wide range of pore sizes have been produced. 

Recently, a dual template method using both polystyrene spheres and silica particles as templates was reported to result in the preparation of ordered, uniform, macroporous carbons with mesoporous walls [254], Figure 2.41a shows the... 

The 3-D macroporous carbons discussed earlier usually possess low crystallinity, partly because their carbonization temperature is relatively low (<1000°C). Very recently, Jaroniec and coworkers reported that a highly ordered, and indeed graphitized, nanoporous carbon with spherical pores can be prepared by heat... 

Lee et al. studied the electrochemical properties of colloidal-crystal-tem-plated macroporous carbon materials in secondary batteries [306]. They found that the characteristics of 3-D ordered macroporous (3-DOM) carbon composed of interconnected pores with wall thickness of a few tens of nanometers enhances the kinetic performance. The authors suggested that improved performance originates from (1) a short solid-state diffusion length for lithium ions, (2) a large... 

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