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Full-Text Articles in Engineering
Electrochemical Filtering Of Co From Fuel-Cell Reformate, Balasubramanian Lakshmanan, Wayne Huang, John W. Weidner
Electrochemical Filtering Of Co From Fuel-Cell Reformate, Balasubramanian Lakshmanan, Wayne Huang, John W. Weidner
John W Weidner
A proton exchange membrane fuel cell was used as a flow reactor for continuous preferential oxidation of CO over H2 from 1.0% CO in H2 under pulse-potential control. By varying the pulse profile ~e.g., on-time, off-time, pulse potential! the CO and H2 oxidation currents were varied independently. The improvement in faradaic selectivity between CO and H2 oxidation results from the promotion of CO adsorption during the off ~i.e., open-circuit! portion of the pulse. Therefore, during the on portion CO oxidation was preferred while the surface was covered with CO.
Development Of A Novel Co Tolerant Proton Exchange Membrane Fuel Cell Anode, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang
Development Of A Novel Co Tolerant Proton Exchange Membrane Fuel Cell Anode, Andrew T. Haug, Ralph E. White, John W. Weidner, Wayne Huang
John W Weidner
Typically Pt is alloyed with metals such as Ru, Sn, or Mo to provide a more CO-tolerant, high-performance proton exchange membrane fuel cell (PEMFC) anode. In this work, a layer of carbon-supported Ru is placed between the Pt catalyst and the anode flow field to form a filter. When oxygen is added to the fuel stream, it was predicted that the slow H2 kinetics of Ru in this filter would become an advantage compared to Pt and Pt:Ru alloy anodes, allowing a greater percentage of O2 to oxidize adsorbed CO to CO2. With an anode feed …
Oxidation Of Borides And Carbides With Y2o3 And Ta Additions, Salvador Manuel Rodriguez
Oxidation Of Borides And Carbides With Y2o3 And Ta Additions, Salvador Manuel Rodriguez
Open Access Theses & Dissertations
The study presented here describes an investigation of an oxidation scale of a fully-sintered Y2O3-ZrB2-TiC composite exposed in air at 1173K. Upon oxidation of the boride/carbide, a ZrO2-TiO2 was expected to form similar to the ZrO2-SiO2 dual scale of an oxidized ZrB2-SiC. The 47wt% Y2O3-38wt%ZrB2-16wt%TiC composite formed a dual scale consisting primarily of an Y2O3-ZrO2-TiC inner scale with an outer scale of ZrO2-TiO2-Y2O3.
The samples oxidized with a parabolic layer growth allowing the calculation of the effective diffusion coefficient indicating that the oxidation was controlled by oxygen ingress through primarily the ZrO2-Y2O3 phase. The oxygen potential between the inner layer …