PDF Publication Title:
Text from PDF Page: 012
Energies 2010, 3 1510 Manganese oxides have attracted increasing interest as oxygen reduction catalysts in alkaline media in recent years. The activity of MnOx depends upon the type of oxide and the carbon support. The most active were the MnO2, Mn2O3 and MnOOH (manganese oxy-hydroxy) oxides [85–87]. The ORR mechanism on these catalysts involves the formation of the HO2− intermediate via the transfer of two electrons followed by a dismutation reaction of this species into OH− and O2. Metal macrocyles have been used as oxygen reduction catalysts since the 1960’s. They have shown high activity towards the ORR in alkaline media. Cobalt and iron phthalocyanine and porphyrins are of the most interest. Co phthalocyanine has exhibited similar kinetics on ORR as Pt [88]. Electrodes made of Cobalt/iron tetraphenylporphyrin (CoTPP, FeTPP) demonstrated good performance, even better than Ag catalyst. Heat treatment of carbon supports can result in structural changes and increase the surface area, resulting in enhanced catalytic activity [89,90]. However, the stability of the catalyst was poor due to loss of Co [91]. It has been reported that iron phthalocyanine (FePc) has the ability to promote the direct 4e– oxygen reduction to water, while CoPc promotes O2 reduction to H2O2 by a 2e− pathway [92–95]. This 4e− pathway is more desirable as it avoids the production of hydrogen peroxide which can damage the electrode structure. One important advantage from MnOx and metal macrocycles to Pt is their insensitivity to fuel and tolerance to alcohol crossover. Carbon supported La1-xSrxMnO3 (LSM/C) was prepared for oxygen reduction with the presence of EG [20]. LSM/C exhibited high activity for O2 reduction regardless of EG. This indicates LSM is a good cathode catalyst in DAAFC with no crossover problem. A Fe-Co nanoparticle based ORR catalyst, Hypermec TM K14 developed by Acta S.P.A, Cascina (Pisa), Italy, was reportedly applied by few groups as the cathode for their alkaline alcohol fuel cells [59,96–98]. Power densities ranging from 55–170 mW cm−2 with different fuel cell configurations and fuels were achieved indicating a very promising catalyst for DAAFCs. 4. Electrolyte and Membrane Electrolyte for DAAFC Most studies of direct alcohol fuel cells have used aqueous alkaline electrolyte or added alkaline in the fuel solutions, as an anolyte [21,49,99,100]. To date the performance of these fuel cells has not matched that achieved with the fuel cells using proton exchange membranes (PEMs) in acidic environment. 4.1. Cation Exchange Membranes Polymer electrolyte materials such as Nafion® are used commercially both for proton transfer and for sodium ion transfer. An example is the electrolysis of sodium chloride to produce chlorine and sodium hydroxide. The conduction process in this system is realised by the transport of Na+ ions from anode to cathode. A practical consequence of DMAFCs operating in such a manner is that hydroxide ions produced by oxygen reduction react rapidly with Na+ ions leading to the formation of sodium hydroxide in the cathode side of the cell. In addition, water is transported across the cell to the cathode. This being the case, it is necessary to recycle this component to the anode to maintain an overall sodium ion balance in the system. A schematic diagram of the electrochemical reactions and transport processes in such a system is shown in Figure 3. The performance of a Na+ conducting Nafion based DMFC has been studied [101]. Although the open circuit voltage obtained was favourable (ca. 0.8 V), in comparison to DMFCs operating in acidic media, the polarisation of the DMAFC was greater [102].PDF Image | Aspects of Direct Alkaline Alcohol Fuel Cells
PDF Search Title:
Aspects of Direct Alkaline Alcohol Fuel CellsOriginal File Name Searched:
energies-03-01499.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)