Vulcan XC-72 carbon black

Bimetallic Pt-Ru/C NPs of around 2.5-3.5 nm have been prepared by reduction of H2PtCl6, RuCb and Vulcan XC-72 carbon black dispersed in BMI.BF4 and they possess high electrocatalytic activity for methanol oxidation [132]. 

At present, electrocatalysts generally are supported on high-surface-area carbon blacks (CBs) with a high-mesoporous distribution and graphite characteristics, and Vulcan XC-72 carbon blacks (Cabot International) are the most commonly used carbon support because of their good compromise between electronic conductivity and Brunauer-Emmett-Teller s (BET s) surface area. However, the effect of the surface characteristics of the various carbon materials had not been fully studied to our best knowledge. 

A 3-D ordered macroporous carbon loaded with Pt-Ru alloy particles was evaluated for electrochemical performance in a DMFC [248,251], The carbon displayed advantages over Vulcan XC-72 carbon black. Another study also showed that a Pt-Ru catalyst supported on ordered macroporous carbon exhibited higher specific activity for methanol oxidation than the commercial E-TEK catalyst [254], We also demonstrated that the electrochemical properties of Pt catalysts, supported on microporous carbon with an amorphous carbon core/ graphitic carbon shell structure [75,337], on an OMC [135], and on a 3-D macroporous carbon [256] improved the specific activity of methanol electrochemical oxidation at room temperature. 

FePc, CoPc, FeCy, CoCy Vulcan XC-72 carbon black 2h Ar 600-800 1 M H2SO4 [117]... 

In the electrodes for PAFC, the Vulcan XC-72 carbon black is most widely used catalyst support material [95]. The oxidation of Vulcan carbon black in the presence of phosphoric acid at 191 °C showed that the disordered central part of carbon particles was oxidized while the outer crystalline part remained intact [96]. Among the attempts to improve the oxidation resistance of Vulcan carbon black, the most widely used method is the heat treatment which increases the level of graphitization on the carbon surface [97]. The heat treatment of Vulcan carbon black at the temperature of 2200 °C which reduced the surface area of Vulcan from 240 to 80 m /g improved oxidation resistance more than twofold [98, 99]. Other highly graphitic carbon materials such as CNT [100] and graphene [101] have been used as support materials because of their high surface area and electrical conductivity. When selecting the carbonsupport material, the oxidation resistance is the critical property for carbon supports to enhance the durability of HT-PEMFC MEAs however, the surface area, shape, and size of support material should also be considered to achieve the desired dispersion of Pt particles as well as the pore structure within the catalyst layer. 

In Table 14.1 the overall and hydrophilic pore snrface areas of SWCNTs and of SWCNTf s are listed as well as the true surface area of Pt-Ru catalyst found by measuring the amount of electric charge needed for the oxidation of adsorbed carbon monoxide. The catalyst s specific surface area was found as a ratio of the true surface area and the amount of metals deposited. For comparison, data for Vulcan XC-72 carbon black are also shown. 

Measurements of the catalyst s specific surface area on different supports show that for very small deposit amounts (4 to 5 p,g/cm ) on SWCNTf s, high values (250 to 350 m /g) of this specific area can be reached. These values are much lower on original SWCNTs and on Vulcan XC-72 carbon black. Wifh increasing deposition time the crystallite size increases and the specific area decreases. For a... 

For this type of fuel cell, a number of reports studying anode MPLs have been published. Neergat and Shukla [124] used a hydrophobic MPL on the cathode (carbon black and PTFE) and a hydrophilic MPL on the anode (carbon black and Nafion) (see Section 4.3.2). Different types of carbon particles were used (Vulcan XC-72, acetylene black, and Ketjenblack) and it was concluded that Ketjenblack was the carbon that showed the best performance when it was used on both the anode and cathode MPLs with 10 wt% Nafion and 10 wt% PTFE, respectively. A similar design was also used by Ren et al. [173] in a passive DMFC. Improvement of the DMFC performance by using a hydrophilic MPL, as discussed previously, was also demonstrated by Lindermeir et al. [125]. They compared both hydrophilic and hydrophobic MPLs for the anode DL, and it was observed that the former improves the mass transport of the MEA. 

Carbon black is favorable as a support material not only because of its high surface area and electronic properties, but it is also abundant, chemically inert, and environmental friendly (Bleda-Martinez et al., 2007). Carbon blacks are typically used as supports which are manufactured by the pyrolysis of hydrocarbons or oil fractions using oil furnaces or acetylene processes. Some of the most common carbon blacks used for platinum deposition in PEMFC catalysts are synthesized using the furnace method where the input materials are burned with hmited air at about 1400°C (Dowlapalli et al., 2006). Vulcan XC-72 and Black Pearl 2000 represent these types of carbon blacks. These carbon blacks are easily made and abundant making them popular choices for carbon black supports for Pt/C catalysts (Cameron et al., 1990). 

Unlike with carbon paper, both sides of the carbon cloth were coated with a carbon/PTFE mixture to form a gas diffusion half-layer (GDHL) on each side, then the CL was applied onto one of the GDHLs. The results suggested that fuel cell performance can be improved under high pressure by using cathodes with Vulcan XC-72 carbon powder on the catalyst side and acetylene black on the gas side. 

So far, the Pt-Ru alloy has shown the most promising performance for the oxidation of methanol and hydrogen oxidation reaction in the presence of CO. Carbon black has been used as support for the metal nanoparticles, particularly Vulcan XC-72 (Cabot), which has a surface area of 240 m g . Methanol oxidation starts at lower potential values for all the Pt-Ru/C catalysts than for Pt/C anodes. Comparison of electrodes prepared with Pt and Pt-Ru as the electrocatalyst supported on nanotubes and those prepared with the most usual support, Vulcan XC-72 showed that multi-wall carbon nanotubes produce catalysts (Pt-Ru/MWNT) with better performance than on other supports, particularly with respect to those prepared with the traditional Vulcan XC-72 carbon powder [18],... 

Fig. 14. Electron micrographs of electrically conductive grades of carbon black where (a) is Vulcan XC-72 (Cabot) (100, OOOx ) and (b) is Vulcan P (Cabot)...

Shao et al. [35] not only used a similar Ti mesh to the one presented by Scott s group but also used a Ti mesh as the cathode DL in a DMFC. The main difference between both meshes was that the one used on the cathode side was coated on both sides with carbon black (Vulcan XC-72) and PTFE (i.e., with MPLs on each side). It was shown that this novel cathode DL performed similarly to conventional CFP DLs under comparable conditions. Chetty and Scott [36] also used a catalyzed Ti mesh as the anode DL, but in a direct ethanol fuel cell (DEFC) it performed better compared to a cell with a standard DL (CFP). 

Wang et al. [140] presented another example of multilayered MPLs that consisted of a basic MPL (Vulcan XC-72 and PTFE) on top of a DL and a mixfure of carbon black (Black Pearl 2000) and Nafion sprayed onfo fhe peripheral region of the MPL (i.e., around the active area). Tliis was done on both the anode and cathode sides. The extra MPL, also called a water transfer region (WTR), was used in order for fhe MEA to be self-humidified. The WTR would receive the excess water at the cathode and then the water... 

For the preparation of the electrocatalyst or catalytic ink, a predetermined amount of carbon black (VULCAN XC 72) was added to the Sb-doped Sn02 sol and stirred at room temperature for several hours. The carbon black was then washed thoroughly with water and dried at 100°C for 1 h followed by further drying at 500°C under nitrogen for 30 min. 

We have also tested the effect of the matrix material on the activity of COj reduction. Figure 2 shows the catalytic activities of ACF/Ni comparing two carbon black matrix materials Vulcan XC-72 (Cabot Corp.) and Denka acetylene black (AB). When XC-72 was used, the partial current density for COj reduction saturated at -2.0 V vs SCE. However, in the case of AB, the partial current density continued to increase with increasing potential. The difference may be due to the fact that AB, being more hydrophobic than XC-72, allows more COj molecules to reach the catalyst pores. 

Figure 2 HREM image of a Pd particle captured by the support matrix. The particle is formed via spontaneous reduction of aqueous H2PdCl4 by the surface of carbon black Vulcan XC-72 at 20 °C.

Pt-doped carbon aerogels have been used successfully in the preparation of cathode catalyst layers for oxygen reduction reaction (ORR) in PEMFC systems [83-86]. Thus, different Pt-doped carbon aerogels with a Pt content of around 20 wt% were prepared by impregnation [83]. Results obtained with these Pt catalysts were compared with others supported on carbon blacks Vulcan XC-72 and BP2000, which are commonly used as electrocatalysts. The accessibility of the electrolyte to Pt surface atoms was lower than expected for high-surface-area... 

PVB) 100,000 (PCL) 35,000 Vulcan XC-72 conductive carbon black (5 vol%) CB roll-mixed blend films from THF solutions crystallization temperature of 41°C As above and also with fullerene (5 vol%)... 

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