Ordered mesoporous carbons applications

The next two chapters deal mainly with the use of adsorption to characterize porous solids. In the case of activated carbon fibers (Chapter 17), methods to characterize microporosity, and particularly ultramicroporosity, by physical adsorption are of particular relevance for understanding the behavior of these adsorbents and extending the range of their applications. Moreover, in Chapter 18 the pore structure of ordered mesoporous carbons is shown to differ greatly from that of conventional activated carbons for which most of the available data treatment methods have been developed. Therefore, suitable procedures for correctiy analyzing the pore structure of these novel carbons are proposed in this chapter. 

Ordered) mesoporous carbons are an interesting class of carbon materials for fuel cell applications, as they offer a means to control the porosity on the micro- and mesoscale, which is important with respect to the accessibility and addressability of the active metallic nanoparticles. The pores should allow access of the ionomer to transfer protons away from the reaction sites. Moreover, the pores should not be too small so that they can get clogged or expensive noble metal particles buried inside them. In this case, they would not contribute to the electrochemical performance. 

Hierarchically ordered mesoporous carbons (HOMC) are attractive as a support for fuel cell applications because of their interconnected bimodal pore-size distribution. Both pore systems can be mesoporous or one can be mesoporous while other can be macroporous. While a mesoporous pore structure imparts high surface area and uniform distribution of catalyst particles, macropores provide efficient mass transfer. Of course, the interconnectivity between pores has a significant role in realizing the advantages of both pore stmctures. Also, a novel feature about these structures is that the two pore structures can be adjusted independently, allowing for good control over their porosity [73, 74]. Like OMC, controllable pore structure, and carbon microstracture and surface chemistry, makes them an attractive support for fuel cell catalysis. Fang et al. have shown that Pt on hollow... 

Ordered mesoporous carbon-supported nano-platinum catalysts application in direct methanol fuel cells... 

Kuppan, B. Ordered mesoporous carbon-supported platinum electrocatalysts for direct methanol fuel-cell application. PhD Thesis, IIT-Madras, India, 2014. 

Liu, H.-X, Wang, X.-M., Cui, W.-X, Dou, Y.-Q., Zhao, D.-Y. Xia, Y.-Y Highly ordered mesoporous carbon nanofiber arrays from a crab shell biological template and its application in supercapacitors and fuel-cells. J. Mater Chem. 20 (2010), pp. 4223 230. 

Lin, M.-L., Huang, C.-C., Lo, M.-Y., and Mou, C.-Y. (2008) Well-ordered mesoporous carbon thin film with perpendicular channels application to direct methanol fuel cell. Journal of Physical Chemistry C, 112 (3), 867-873. 

Jia N, Wang Z, Yang G, Shen H, Zhu L (2007) Electrochemical properties of ordered mesoporous carbon and its electroanalytical application for selective determination of dopamine. Electrochem Commun 9 233-238... 

Ndamanisha JC, Bai J, Qi B, Guo L (2009) Application of electrochemical properties of ordered mesoporous carbon to the determination of glntathione and cysteine. Anal Biochem 386 79-84... 

It should be mentioned that the structure of carbon supports could have significant influence on the electro-catalytic properties of the nanocomposite catalysts. Recently, Pt/Ru nanoclusters prepared by the alkaline EG method were impregnated into a synthesized carbon support with highly ordered mesoporous. Although the Pt/ Ru nanoclusters can be well dispersed in the pores of this carbon substrate, the long and narrow channels in this material seem not suitable for the application in... 

Since the discovery of ordered mesoporous materials, researchers have explored many possible applications that can take advantage of the unique compositional or structural features of mesoporous materials. In addition to apphcations in traditional areas such as catalysis, separation, and ion exchange, new applications that might involve mesoporous materials include stationary phases in HPLC, bio and macromolecular separations, low dielectric constant materials, enzyme immobilization, optical host materials, templates for fabrication of porous carbons, and reactions in confined enviromnents. 

However, research on carbon nanotubes has opened new avenues in the area of materials science and carbon surface derivatization. Their physical and chemical modifications offer excellent opportunities not only in the characterization and understanding of CNT chemistry, but also in highlighting their potential applications. In the context of this chapter, one important application of CNTs is their use as support for homogeneous catalysts in fact, based on the very few examples published in the literature, this is clearly a very promising area. Furthermore, the potential extrapolation of the CNT derivatization methodologies to more traditional and other recent carbon materials (mesoporous and ordered porous carbon materials) is also one of the major challenges for all researchers who are involved with carbon materials. 

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. 

Several reviews covering the synthesis, properties and applications of porous carbons, especially mesoporous carbon materials, can be found in the literature. In this chapter, we summarise the recent developments in the synthesis and characterisation of templated porous carbon materials. Particular attention is paid to the synthesis of structurally ordered porous carbon materials with narrow pore size distribution via both hard and soft template methods. We especially emphasise those so-called breakthroughs in the preparation of porous carbon materials. The chapter is divided into three sections according to the pore size of carbon materials we first consider the synthesis of microporous carbon materials using zeolites and clays as hard template, then summarise the preparation of mesoporous carbon materials via both hard template and self-assembly... 

The morphology of ordered mesostructured carbons is another important factor with respect to their practical applications. Various macroscopic morphologies are required, for example, films (in sensor, separation and optical applications), uniformly sized spheres (in chromatography) or transparent monoliths. Using suitable synthesis strategies, it is possible to control the external shape of the templated mesoporous carbon materials to generate powders, films and membranes, spheres, hollow spheres, rods, fibres, nanowires, nanotubes and monoliths. 

Alternative interesting applications for porous carbon materials have been recently reported. For example, porous carbons prepared from the large mesopore Fniim silica (KlT-5) demonstrated a superior ability to separate the tea components catechin and tannic add, compared to other p>orous materials, such as activated carbons and mesoporous silica [23]. Porous carbon nitride with a large surface area has been prepared using well-ordered mesoporous silica as a template for the polymerization between ethylenediamine and carbon tetrachloride [24]. In this case, the metal-free carbon nitride was able to function as an efficient basic catalyst for transesterification reactions. 

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,... 

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