PDF Publication Title:
Text from PDF Page: 138
demonstrated with full-scale cells in stacks. Approaches to increase life are to use series fuel gas flow in the stack to alleviate corrosion, provide well-balanced micropore size reservoirs to avoid electrolyte flooding, and use a high corrosion resistant carbon support for the cathode catalyst. These improvements resulted in the lowest PAFC degradation rate publicly acknowledged: 2 mV/1,000 hours for 10,000 hours at 200 to 250 mA/cm2 in a short stack with 3,600 cm2 area cells. UTC Fuel Cells reported a similar degradation rate in 2002 for power units operating up to 40,000 hours (3). Several important technology development efforts for which details have been published include catalyst improvements, advanced gas diffusion electrode development, and tests on materials that offer better carbon corrosion protection. Transition metal (e.g., iron, cobalt) organic macrocycles14 from the families of tetramethoxyphenylporphyrins (TMPP), phthalocyanines (PC), tetraazaannulenes (TAA) and tetraphenylporphyrins (TPP) have been evaluated as O2-reduction electro-catalysts in PAFCs. One major problem with these organic macrocycles is their limited chemical stability in hot concentrated phosphoric acid. However, after heat treatment of the organic macrocycle (i.e., CoTAA, CoPC, CoTMPP, FePC, FeTMPP) on carbon at about 500 to 800 °C (932 to1,472 °F), the pyrolyzed residue exhibits electro-catalytic activity that, in some instances, is comparable to that of Pt and has promising stability, at least up to about 100 °C/212 °F (21). Another successful approach for enhancing the electro-catalysis of O2 reduction is to alloy Pt with transition metals such as Ti (22), Cr (23), V (24), Zr, and Ta (24). The enhancement in electro-catalytic activity has been explained by a correlation between the optimum nearest-neighbor distance of the elements in the alloy and the bond length in O2 (25). Conventional cathode catalysts comprise either platinum or platinum alloys supported on conducting carbon black at 10 wt percent platinum. Present platinum loadings on the anode and cathode are 0.1 mg/cm2 and 0.5 mg/cm2, respectively (12, 16). It has been suggested by Ito, et al., that the amount of platinum may have been reduced to the extent that it might be cost effective to increase the amount of platinum loading on the cathode (26). However, a problem exists in that fuel cell stack developers have not experienced satisfactory performance improvements when increasing the platinum loading. Johnson Matthey Technology Centre (J-M) presented data that resulted in improved performance nearly in direct proportion to that expected based on the increase in platinum (27). Initial tests by J-M confirmed previous results - that using platinum alloy catalyst with a 10 wt percent net platinum loading improves performance. Platinum/nickel alloy catalysts yielded a 49 wt percent increase in specific activity over pure platinum. This translated into a 39 mV improvement in the air electrode performance at 200 mA/cm2. Johnson Matthey then determined that the platinum loading in the alloyed catalyst could be increased up to 30 wt percent while retaining the same amount of platinum without any decrease in specific activity or performance; the amount of nickel, hence the total amount of alloyed catalyst, decreased. Next, J-M researchers increased the amount of platinum from 10 to 30 wt percent while keeping the same nickel catalyst loading. The total amount of alloyed catalyst increased in this case. Results showed an additional 36 wt percent increase in specific activity, which provided another 41 mV increase at 200 mA/cm2. The ideal voltage increase would have been 46 mV for this increase in platinum. Thus, the performance increase obtained experimentally was nearly in 14. See Reference 21 for literature survey. 5-9PDF Image | Fuel Cell Handbook (Seventh Edition)
PDF Search Title:
Fuel Cell Handbook (Seventh Edition)Original File Name Searched:
fuel-cell-handbook.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)