Carbon Toray paper

The activities of CNTs have been evaluated by Girishkumar et al. [7] using ex situ EIS. Their study was conducted in a three-compartment electrochemical cell using a GDE electrode (a carbon fibre paper coated with SWCNTs and Pt black as an anode or cathode). Electrophoretic deposition was used to deposit both the commercially available carbon black (CB) for comparison and the SWCNT onto the carbon Toray paper. Commercially available Pt black from Johnson Matthey was used as the catalyst. In both cases, the loading of the electrocatalyst (Pt), the carbon support, and the geometric area of the electrode were kept the same. EIS was conducted in a potentiostatic mode at either an open circuit potential or controlled potentials. 

FIGURE 10.28 Scanning electron microscopy (SEM) images of (a, b) Umbite and (c, d) ETS-10 supported on carbon Toray paper. (Erom Aused, M.P., Urbiztondo, M.A., MaUada, R., Pina, M.P., and Santamana, J., Synthesis of proton conducting membranes for direct metbanol fuel cells (DMPCs). Books of abstracts of tbe OSSEP Pinal Workshop, Tenerife, 2004, pp. 90-91.)... 

Chandra, B., Race, J.T., Sun, Y., Barton, S.C., and Hone, J. (2007) Growth of carbon nanombes on carbon Toray paper for bio-fuel cell applications. 

In addition to studying the performance of thin-film sputtered R electrodes, the effect of Teflon (PTFE) incorporation in the carbon Toray paper... 

Scanning electron microscope picture of typical carbon fiber paper sheets used in fuel cells (a) Toray TGPH-060 CFP with no PTFE (reference bar indicates 500 pm) (b) close-up view of the TGPH-060 CFP with no PTFE (reference bar indicates 100 pm) (c) Toray TGPlT-060 CFP with 20% PTFE (reference bar indicates 500 pm) (d) close-up view of the TGPH-060 CFP with 20% PTFE (reference bar indicates 100 pm). 

In PEMFCs, Ralph et al. [86] tested a Ballard Mark V single cell with two different DLs a carbon cloth (Zoltek PWB-3) and a carbon fiber paper (Toray TGP-090) all the other operating conditions stayed the same for bofh cases. It was observed that the carbon cloth demonstrated a distinct advantage over the CFP at high current densities (>600 mA/cm ), while at low current densities both DLs performed similarly. If was claimed fhaf this was because the CC material enhanced mass transport properties and improved the water management within the cell due to its porosity and hydrophobicity. 

When the low-flow rate single-cell electrolysis cell was used the cathode and anode were fabricated by painting one side of a 5 cm2 piece of EC-TP1-060 Toray Carbon Fiber Paper with Pt on XC-72R catalyst mixture. In high-flow rate single-cell electrolysis experiments the cathode was a... 

For a more thermally conductive GDL, intermediate between Toray carbon fiber paper and pure graphite, for example, Ks 30 J/(m s °K) with iJr 1, the positive terms dominate, and the vapor flux is toward the membrane. In the... 

Oxygen reduction studies and cyclic voltammetry were carried out at ambient temperature (22 2°C) in 1 cm gas diffusion electrodes as previously described (8). The catalyst, mixed with ca. 50 mass % PTFE as a binder (and Nafion solution in one case), was spread on carbon fibre paper (CFP Toray TGPH090), which was then hot-bond to a Nafion 117 membrane. In the cell, a controlled flow of gas (O2, or N2 for cyclic voltammetry) was passed over the CFP and the membrane was in contact with a 1 M H2S04(aq) solution containing counter and reference (SCE) electrodes. 

The initial porosity of a carbon paper-type GDM is often higher than 75% (Toray paper and SGL paper as high as 80 and 90%, respectively). After teflonization, it may decrease to around 70%, which is still very high. The porosity of the GDM is measured by porosimetry, a technique ideal for measuring pores ranging from a few nm to a few hundred pm. The porosimeter first creates a vacuum condition to remove gases within the pores of the GDM,... 

Table 14.2 shows the porosities (pore volume per unit of sample volume) for hydrophilic pores Uphi, hydrophobic pores Upho, and the overall porosity u = Uphi + Upho for Toray paper with two values of PTFE concentrations cptee-Also shown in the table is the parameter hydrophobizing efficiency which represents the ratio of hydrophobic pores (in volume percent) to the PTFE concentration (in volume percent or, as carbon and PTFE have similar density values, in weight percent). This parameter is of importance since high values of the PTFE concentration can lead to an increase in the GDL s ohmic resistance. From the table it can be seen that the PTFE concentration does not significantly influence the volumes of both hydrophilic and hydrophobic pores. At the same time. 

Polymer-modified electrodes that are prepared by electropolymerization of monomers, with mediating properties toward NADH oxidation, are attractive because the synthesis is irreversible, the long-term stability of the electrode is enhanced, and the catalytic properties of the monomer are retained. A diversity of reports on electropolymerization of o-quinone derivatives [87-89], and phenothiazine and phenoxazine derivatives with different levels of utility for practical applications, can be found in the literature [62,65,66,68,72,90-92], Electropolymerization of azinc derivatives has mainly been reported on gold [66,91], platinum [93], glassy carbon electrodes [65,68,71,81,92,94-97], and other carbonaceous electrode materials (Toray paper [98-100], graphite [101], and screen-printed carbon [70]). 

Toray carbon fibar paper diffusion media (TGP-H at 57°C)... 

For an uncompressed Toray TGP-H-060 carbon fiber paper, the Darcy coefficient of 5-10 X 10 m has been reported [31]. Approximately the same value has been reported for in-plane flow through the same material compressed to 75% of its original thickness [31]. 

MEAs used in this study were prepared in the following procedure [5]. The diffusion backing layers for anode and cathode were a Teflon-treated (20 wt. %) carbon paper (Toray 090, E-Tek) of 0.29 mm thickness. A thin diffusion layer was formed on top of the backing layer by spreading Vulcan XC-72 (85 wt. %) with PTFE (15 wt. %) for both anode and cathode. After the diffusion layers were sintered at a temperature of 360 C for 15 min., the catalyst layer was then formed with Pl/Ru (4 mg/cm ) and Nafion (1 mg/cm ) for anode and with Pt (4 mg/cm ) and Nafion (1 mg/cm ) for cathode. The prepared electrodes were placed either side of a pretreated Nafion 115 membrane and the assembly was hot-pressed at 85 kg/cm for 3 min. at 135 C. 

In DMFCs, methanol crossover and carbon dioxide gas management are critical issues that have be dealt with. Argyropoulos, Scott, and Taama [98] used a transparent fuel cell (fhe anode end plate was made out of acrylic) to visualize the CO2 evolution and management on the anode side. Both CFPs and CCs were used as anode DLs and it was observed that CFP (Toray carbon paper) was not a suitable material due to its poor gas removal properties. 

Polarization curves for Toray carbon paper 260 and carbon cloth A. (Modified from A. Oedegaard et al. Journal of Power Sources 127 (2004) 187-196. With permission from Elsevier.)... 

The separator used was a Nation membrane. Each electrode was separated by a carbon paper disk (Toray TGP-H-090) from the Ti plate current tap to minimize contact resistance. The assembled cell was immersed into 1M H2S04(aq) to impregnate electrodes by electrolyte. 

Fig. 7.13 SEM images of Toray TGP-H-60 carbon paper at 200x (a) and 400x (b)...

Toray carbon paper specification (2005) http //www.torayca.com/en/index.html. Accessed 18 July 2012... 

Toray market a porous carbon paper and carbon cloth which can be pretreated with Teflon in a hydrophobic form and can then be used directly for electrode manufacturing. It is able to conduct a current, support a catalyst and allow gases and liquids to pass through. 

In order to increase the sensitivity of fluorescence imaging, the effect of catalyst loading and time on the intensity was studied using Pt and PtSn [128]. The best measurements were obtained with 0.25 pmol cm catalyst load on Toray carbon paper, whilst the long-term catalyst performance could be visualized as a decrease in the brightness of the fluorescence spots in time, monitored by a CCD camera. 

The stress-stram curves for PTL materials over a wide range of compressive loads (0-5 MPa) have been measured (Escribano et al., 2006 Nitta et al., 2008). Nitta et al. attributed the variations at small loads (<0.2 MPa) to small differences in surface roughness across the samples. They also discussed two hnear regions on the curves that were attributed to the sequential deformation due to the collapse of hydrophihc and hydrophobic pores. More recently, Sadeghi et al. (2008,2010a,b) reported measurements on circular samples of 78% porous Toray carbon papers under static and cyclic loads of up to 1.5 MPa. These measurements revealed significant hysteresis in the measured parameters (porosity, thickness, etc.) with subsequent stabilization within a few cycles. A summary of representative data sets is plotted in... 

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