Fuel cells have the potential to solve several major challenges in the global energy economy: dependence on petroleum imports, degradation of air quality, and greenhouse gas emissions. Using catalyst-based reformer technology, hydrogen for fuel cells can be derived from infrastructure fuels such as gasoline, diesel, and natural gas. Platinum is one catalyst that is known to be very effective in hydrogen reformers. Reformer size can be reduced when there is more efficient catalyst loading onto the substrate. In this experimental work, platinum was loaded onto -alumina coated substrates by plasma-polymerization followed by heat treatment. Vapor from a platinum-containing organic precursor was converted to plasma and deposited onto the substrate. The plasma-polymerized film was then calcined to drive off organic material, leaving behind a catalyst-loaded substrate. The plasma-polymerized organic film and the final heat-treated catalyst-loaded substrate surface were characterized by scanning electron microscopy (SEM) and impedance spectroscopy. Energy dispersive spectroscopy (EDS) was used to detect the presence of the catalyst on the substrate.Index Terms-Catalyst loading, fuel reformer, plasma-enhanced metal-organic chemical vapor deposition (PEMOCVD), plasmapolymerized film, platinum.
Mechanical and Materials Engineering for extending the use of their laboratory facilities and providing useful comments. I would like to thank Scott Cornelius and Charles M. Knaack, Department of Geology, for helping me with EDS and ICPMS analysis respectively. I would like to thank Chris Davitt and Valerie Lynch-Holm, Electron Microscopy Center, for providing hands on training on SEM and TEM. I would also iv express my thanks to Dr. Thompson and Anna Sekar Darujati for helping me with XRD. I would also express my gratitude to John Yates, John Grimes and other staff who provided valuable equipment fabrication support. I would like to thank my family, my mom and dad, without whose support I couldn't have accomplished whatever I had to. I know I have missed them a lot especially my dear younger sister Romila, during my stay in Pullman. Lastly, I would like to thank all my friends here in Pullman, especially Satish, Jagan and Ravindra, who really made my stay enjoyable and worthwhile. v
In one hydrogen-based energy system, fuel cells utilize hydrogen and oxygen to produce electricity while reformers produce hydrogen from infrastructure fuels such as gasoline, diesel and natural gas. Reformers based on microchannel technology require a catalyst dispersed throughout a porous support, while the support must adhere to the substrate. In this work, support and catalyst were deposited (onto Fecralloy? in alternate layers of plasma-polymerized platinum acetylacetonate and zirconium acetylacetonate, denoted Pt(acac)2 and Zr(acac),, respectively. After exposing the composite organic film to heat treatment, most organic constituents were volatilized and platinum-loaded zirconia remained. The plasma reactor consisted of a 10 cm inside diameter Pyrex" tube evacuated to a base pressure of 5 x IO4 Torr and surrounded by a 4-turn 13.56 MHz RF coil. Non-equilibrium, inductively-coupled plasma was generated by applying RF fields to a precursor vapor plume emanating from a heated sublimator crucible. Plasma processing took place directly in the precursor vapor without added camer gas. Plasma-polymerization of the Pt(acac), and Zr(acac), resulted in deposition oforganic film on the Fecralloyo. In a typical fabrication mn, six 4 pm thick layers of plasma-polymerized Pt(acac), and nine I W t n thick layers of plasma-polymerized Zr(acac), were interleaved and heat treated. The intermediate organic composite film and the final synthesized platinum-loaded support adhering to the Fecralloyo have been evaluated with profilometry, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), inductively coupled plasma-mass spectroscopy (ICP-MS) and a water gas shift (WGS) reactor, Cubic phase platinum and cubic phase zirconia have been detected on the Fecralloya. This catalytic material had a measurable influence on carbon monoxide concentration in a WGS reactor in the temperature range 400-500 C, thus demonstrating catalytic activity in this high temperature range. *Supported by Washington Technology Center (WTC), Seattle, WA 98195-2140 under project number F03-A2.
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