Platinum on carbon black

Identified a preparation for platinum on carbon black catalyst that provides -60% reduction in precious metal grams/kW compared to current commercial preparations... 

Table 2. Comparison of Oiganic Method Platinum on Carbon Black vs. Commercial Catalyst (cathode metal only)...

Premion iridimn (IV) oxide, (Alfa Aesar), Ft catalyst HiSpec 4000 (40% platinum on carbon black w/w, supplied by Alfa Aesar) and a homemade iridimn (IV) catalysts were used in the various MEA. The homemade iridium (IV) oxide was prepared according to the Adams ... 

Phosphoric Acid Fuel Cell This type of fuel cell was developed in response to the industiy s desire to expand the natural-gas market. The electrolyte is 93 to 98 percent phosphoric acid contained in a matrix of silicon carbide. The electrodes consist of finely divided platinum or platinum alloys supported on carbon black and bonded with PTFE latex. The latter provides enough hydrophobicity to the electrodes to prevent flooding of the structure by the electrolyte. The carbon support of the air elec trode is specially formulated for oxidation resistance at 473 K (392°F) in air and positive potentials. 

The platinum concentrations in the platinized carbon blacks are reported to be between 10 and 40% (by mass), sometimes even higher. At low concentrations the specific surface area of the platinum on carbon is as high as lOOm /g, whereas unsupported disperse platinum has surface areas not higher than 10 to 15m /g. However, at low platinum concentrations, thicker catalyst layers must be applied, which makes reactant transport to reaction sites more difficult. The degree of dispersion and catalytic activity of the platinum depend not only on its concentration on the carrier but also on the chemical or electrochemical method used to deposit it. 

It was seen when studying mixed systems Pt-WOj/C and Pt-Ti02/C that with increasing percentage of oxide in the substrate mix the working surface area of the platinum crystallites increases, and the catalytic activity for methanol oxidation increases accordingly. With a support of molybdenum oxide on carbon black, the activity of supported platinum catalyst for methanol oxidation comes close to that of the mixed platinum-ruthenium catalyst. 

Higuchi E, Uchida H, Watanahe M. 2005. Effect of loading level in platinum-dispersed carbon black electrocatalysts on oxygen reduction activity evaluated by rotating disk electrode. J Electroanal Chem 583 69-76. 

The electrochemical reactions occur on highly dispersed electrocatalyst particles supported on carbon black. Platinum (Pt) or Pt alloys are used as the catalyst at both electrodes. 

Recently, the Pt NMR of commercial fuel cell electrode material has been observed 180,181) (Fig. 61). This material consists of platinum supported on carbon black and pressed into graphitized-carbon cloth. (Similar material has been used to study NMR see Section IV.G.) Because of the conducting nature of the carrier, one might expect to see differences with respect to NMR of particles supported on oxides. Furthermore, if an electrolyte is present in the NMR sample, the electric double layer at the metal/electrolyte interface might influence the Pt surface signal. 

Sepulveda-Escribano, A., Coloma, F., and Rodriguez-Reinoso, F. (1998). Platinum catalyst supported on carbon blacks with different surface chemical properties. Appl. Catal. A (General), 173, 247-57. 

Of interest is the oxidation of a-D-glucopyranosyl dihydrogen phosphate, in the presence of platinum-on-carbon or platinum black, to the corresponding uronic acid which can be isolated as the dicalcium salt in good... 

Membrane fuel cells have zero-gap electrodes on both sides of the membrane. Typically the electrodes are made of a carbon fiber mat impregnated with platinum on carbon (Pt/C) catalyst. To achieve an extended surface for the gas to be adsorbed and react and to maintain continuity for ionic transport, interpenetration of electrode and membrane is necessary. This is usually accomplished by impregnating the porous electrode with. Nafion solution. One assembly technique is to suspend the Pt/C in Nafion solution by sonication and spray it onto carbon paper. Then the membrane is hot pressed between the two impregnated electrodes [44]. Another approach is to make an aqueous suspension of three powders - Pt/C, carbon black, and PTFE - and spray it onto the carbon paper. Then 5% Nafion solution is applied by spraying or by floating the electrode on the Nafion solution, after which the membrane is pressed between the electrodes [45]. The Nafion solution serves as an adhesive as well as a means of extending the electrolyte into the structure of the porous electrode. 

Platinum based catalysts supported on carbon black allowed to significantly increase the power density per electrode area as compared to platinum black type catalysts. The pore system of the support material allows to increase the platinum dispersion and partially prevents migration and the agglomeration of nanoparticles thus leading to a higher specific surface area. 

One can also mention the case of composites-based conducting polymers electrodeposited and characterized on anodes of platinum- or carbon black- filled polypropylene from a stirred electrolyte with dispersed copper phthalocyanine. The electrolytic solution contained, besides the solvent (water or acetonitrile), the monomer (pyrrole or thiophene) and a supporting electrolyte. Patterned thin films were obtained from phthalocyanine derivatives, as reported in the case of (2,3,9,10,16,17,23,24-oktakis((2-benzyloxy)ethoxy)phthalocyaninato) copper . Such films were prepared by means of capillary flow of chloroform solutions into micrometer-dimension hydrophobic/hydrophilic channels initially created by a combination of microcontact printing of octadecylmercaptan (Cig-SH) layers on gold electrodes. These latter gave birth to a hydrophobic channel bottom while oxidative electropolymerization of w-aminophenol (at pH 4) led to hydrophilic channel walls. 

The deposition of ultrafine platinum particles on carbon black by surface ion... 

Zhou ZY, Huang Z-Z, Chen D-J, Wang Q, Tian N, Sun S-G (2010) High-index faceted platinum nanocrystals supported on carbon black as highly ellicicmt catalysts for ethanol electrooxidation. Angew Chem Int Ed 49(2) 411-414... 

In the present article, the size and the loading efficiency of metal particles were investigated by changing the preparation method of carbon-supported platinum catalysts. First, the effect of acid/base treatment on carbon blacks supports on the preparation and electroactivity of platinum catalysts. Secondly, binary carbon-supported platinum (Pt) nanoparticles were prepared using two types of carbon materials such as carbon blacks (CBs) and graphite nanofibers (GNFs) to check the influence of carbon supports on the electroactivity of catalyst electrodes. Lastly, plasma treatment or oxyfluorination treatment effects of carbon supports on the nano structure as well as the electroactivity of the carbon supported platinum catalysts for DMFCs were studied. 

The typical catalyst in fuel cells is platinum (and possibly other platinum group metals). Usually, nanoparticles of these metals are applied on carbon black as a conductive, hydrophilic carrier. In alkaline solution also silver is suitable for ORR. The moderate price of silver permits the application of pure metal as catalyst without a carrier. Additionally, the high conductivity of silver is advantageous. No silver is lost during operation and can be recycled after the ODC service life. However, the high fixed capital may be a problem. 

The Raney nickel catalyst can usually be stabilized by 2 to 4 wt% titanium and additionally activated by a small percentage of molybdenum [95] or platinum [97]. Although Raney nickel has excellent hydrogen adsorption ability and relatively large surface area, some disadvantages have also been reported, such as high electrolyte diffusion resistance due to low pore volume and small pore size [98, 99], and insufficient conductivity [97]. One type of mitigation is to support Raney nickel on carbon blacks, which will decrease its electrolyte diffusion resistance and increase its electrical conductivity [97]. 

Yang et al. (2006) used a PVA/SSA membrane of their own make obtained by cross-linking of poly(vinyl alcohol) with 10 wt% sulfosuccinic acid. In a methanol-air fuel cell with such a membrane, they used 4 mg/cm Pt-Ru on carbon black as the anode catalyst and an inexpensive catalyst without platinum on the basis of Mn02 as the cathode catalyst. The electrolyte was 2 M KOH solution +2M CH3OH. At a temperamre of 30°C, the current density in the maximum-power point was about 10 mA/cm and the voltage was 0.245 V. At 60°C, the corresponding values were 15.4 mAJan and 0.268 V. 

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