Carbon nanofiber membranes

Folyacrylonitrile (FAN) in powder form with an average molecular weight of 1.5 X 10 g/mol and melting temperature of 317 °C was obtained from Sigma-Aldrich Inc. (St. Louis, MO). The FAN powder was heated to 105 °C for 3 h before use, to remove any residual moisture in the powder. 

Collected nanofiber mats were kept overnight in the fume-hood to allow the solvent to evaporate. Subsequently, the mats were placed in an air-circnlated oven at 120 °C for 3 h to remove any trace solvent that might be present in the nanofiber mat. After this the membranes were allowed to cool to room temperatnre and then heated to 250 °C at a heating rate of 5 °C/min. Each membrane was held at 250 °C for at 

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Fig. 8.46 Adsorption capacity of monochloroacelic acid (MCAA) on carbonized nanofiber membranes made from PAN solutions of different concentrations. The membranes were prepared by heating to 250 °C for6 h and then carbonizing at 600 °C for 4 h under nitrogen. (From [17])...

The removal of disinfection by-products (DBFs) was attempted using carbonized nanofilter membranes. Chloroform and monochloroacetic acid were used as the model for DBF compoimds. The main mechanism of removal of the monochloroacetic acid and chloroform was observed to be due to adsorption. The removal efficiency of the species increased when the feed concentration decreased or the surface area of the carbonized nanofiber membrane increased. 

A. M. Kannan and L. Munukutla. Carbon nanochain- and carbon nanofibers-based gas diffusion layers for proton exchange membrane fuel cells. Journal of Power Sources 167 (2007) 330-335. 

In this chapter, we reviewed the structure-controlled syntheses of CNFs in an attempt to offer better catalyst supports for fuel cell applications. Also, selected carbon nanofibers are used as supports for anode metal catalysts in DMFCs. The catalytic activity and the efficiency of transferring protons to ion-exchange membranes have been examined in half cells and single cells. The effects of the fiber diameter, graphene alignment and porosity on the activity of the CNF-supported catalysts have been examined in detail. 

Liu, W. and S. Adanur, Properties of electrospnn polyacrylonitrile membranes and chemically-activated carbon nanofibers. Text. Res. J. 2010,80(2), 124-134. 

On the other hand, the oxidative coupling reaction of CH4 in the presence of Og, even when performed in membrane-type reactors, is mainly catalysed by metal oxide catalysts. Also oligomerisation, aromatisation and the partial oxidation to methanol or formaldehyde apply non-metallic heterogeneous catalysts (i.e. zeolites, supported metal oxides or heterogenized metalcarbon nanofibers or nanotubes from methane, these being catalysed by metal nanoparticles, but at the moment this is not considered as a Cl chemistry reaction. Again we direct the attention of the reader to some reviews on this type of process. ... 

As compared to mesoporous oxide nanofibers, much lesser attention has been paid to their mesoporous amorphous carbon analogues. However, mesoporous carbon exhibits superior resistance to acids and bases, excellent heat resistance, as well as high intrinsic electric conductivity. Potential applications for hybrid membranes consisting of mesoporous carbon within hard templates include size-selective electrosorption, electrosynthesis of nanostructures, catalysis, separation and storage. The first reported procedure for the synthesis of mesoporous carbon nanofibers involved the preparation of... 

Commercially available siHca materials (e.g., Merck Silica 60 and 100) are the support of choice mainly because of practical reasons such as favorable particle size distribution for apphcation in bench-top reactors, while other inorganic supports (AljOj, Ti02, Zr02, etc.) are used less frequently. These materials are resorted to when stability at high pH values is necessary. Other catalyst support materials such as carbon nanofibers [8], membranes [9], and porous polymers [10] have been used as well, albeit sparingly. In an elegant example, Virtanen et al. [11] immobilized an IL on an activated carbon doth. 

The prineiple appheation of a carbon nanofiber hydrogen storage medium is in a fuel tank for an integrated on-board fuel cell system with a polymer electrolyte membrane (PEM) fuel eell stack at its core and a hydrogen supply stored as adsorbed hydrogen in a pressurized tank containing carbon nanofibers. 

A new group of fuel cell is microbial fuel cells (MFCs), which is a novel technology that produces electricity using bacteria as electrocatalysts. The performance of MFCs is influenced by the type of electrode, the electrode distance, the type and surface area of their membrane, their substrate and their microorganisms. The most common catalyst used in cathodes is platinum (Pt). Ghasemi et al. applied chemically and physically activated carbon nanofibers as an alternative cathode catalyst to platinum in a two-chamber microbial fuel cell for the first time [155]. 

Guha, A. et al. (2001). Synthesis of Novel Platinum/Carbon Nanofiber Electrodes for Polymer Electrolyte Membrane (PEM) Fuel Cells. 

Aran H C, Benito S P, Luiten-OliemanMW J,Er S,Wessling M,Lefferts L,BenesN E and Lammertink R G H (2011), Carbon nanofibers in catalytic membrane microreactors , J Membrane Sci, 381,244-250. 

Wang J, Chen Y, Zhang Y, lonescu MI, Li R, Sun X, Ye S, Knights S (2011) 3D boron doped carbon nanorods/carbon nanofiber hybrid composite synthesis and application in highly stable proton exchange membrane fuel cell. J Mater Chem 21(45) 18195-18198... 

Chen D, Liu T X, Zhou X P, Tjiu C W and Hou H Q (2009) Electrospinning fabrication of high strength and toughness polyimide nanofiber membranes containing multiwalled carbon nanotubes,... 

Wu, Q., et al. (2010). Study of Fire Retardant Behavior of Carbon Nemotube Membranes and Carbon Nanofiber Paper in Carbon Fiber Reinforced Epoxy Composites. Carbon, 48(6), 1799-1806. 

Figure 14.17. Schematic diagram of the fahiication of Pt-CNFs using an AAO membrane template [125]. (Reprinted from Chemical Physics Letters, 398(4—6), Zhang L, Cheng B, Samulski ET, In situ fabrication of dispersed, crystalline platinum nanopartieles embedded in carbon nanofibers, 505-10, 2004, with permission from Elsevier.)...

Performance of Carbon Nanotubes and Nanofibers Membrane Electrode Assembly... 

Chen, D. Liu, T. Zhou X. Tjiu, W. C. Hou, H. (2009). Electrospinning Fabrication of EEgh Strength and Toughness Polyimide Nanofiber Membranes Containing Multiwalled Carbon Nanotubes. /, Phys. Chem. B, Vol. 113, No. 29, (July, 2009) pp. 9741-9748, ISSN ... 

Celebi, S., Nijhnis, T., van der Schaaf, J., et al. (2011). Carbon Nanofiber Growth on Carbon Paper for Proton Exchange Membrane Enel, Carbon, 49, pp. 501—507. 

In this connection it can be noted that Guha et al. (2010) investigated the influence of carbon support morphology on the behavior of a PEMFC membrane electrolyte assembly. Platinum electrocatalyst particles were deposited on lower-surface-area fibrous (carbon nanofibers) and particulate (carbon blacks) supports. The performance was shown to be independent of the carbon support morphology. 

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