| John P. Gabaldon, Chemical and Nuclear Engineering, Center for Micro-Engineered Materials, 1 University of New Mexico, Albuquerque, NM 87131, Travis R. Conant, Chemical and Nuclear Engineering, University of New Mexico, 1 University of New Mexico MSC 01 1, 203 Farris Engineering Center, Albuquerque, NM 87131, Levi R. Houk, Center for Micro-Engineered Materials, University of New Mexico, 1 University MSC 01 1120, Albuquerque, NM 87131 and Abhaya Datye, Center for Micro-Engineereed Materials, University of New Mexico, 1 University of New Mexico, Albuquerque, NM 87131
Platinum is a proven industrial catalyst used for reactions ranging from petroleum cracking to CO oxidation. Although, Pt catalyst systems are well studied, the recent synthesis of Pt nanowires by Fukuoka et al.[1] which show high activity for selective CO oxidation has led to increased interest in the role of metal-support interactions for CO oxidation. Most previous work on nanowires is based on batch synthesized mesoporous  templates that have one dimensional pores. In our work, we have synthesized Pt nanowires within aerosol derived silica particles where the pores are contained within spherical particles. The TEM image on the left shows typical images of Pt nanoparticles (NP) and Pt nanowires (NW) within aerosol derived silica particles. The aerosol silica shows no obvious pore termination on the surface, as seen in the figure. In order to use these materials as catalysts, it is important to determine the extent of transport limitations for gas phase reactions, and whether the nanowires exhibit enhanced stability compared with Pt nanoparticles. In our present work, we use the well-studied CO oxidation reaction and the measured Pt surface area via CO chemisorption, to calculate turnover frequencies for NWs and NPs supported within aerosol-derived silica. This data is compared with an open pore Davisil¨, which should provide minimal diffusion limitations. The formation of Pt nanoparticles and wires within a silica template may help to limit the growth in particle size caused by sintering. The presence of Pt within a silica shell may help to protect it from poisons, while at the same time allowing the gas phase reagents easy access to the active phase. References [1] A. Fukuoka, N. Higashimoto, Y. Sakamoto, M. Sasaki, N. Sugimoto, S. Inagaki, Y. Fukushima and M. Ichikawa, Catalysis Today, 66 (2001) 23. Extended Abstract Status: Not Uploaded |