(621d) Mesoporous Crystalline Metal Oxide Supported Au Catalysts
AIChE Annual Meeting
Thursday, November 8, 2007 - 4:24pm to 4:42pm
Here we have developed a novel solution growth of metal oxide nanocrystals within an organized surfactant matrix into mesoporous three-dimensional nanostructured frameworks with tunable mesoporosity. We have successfully synthesized mesoporous crystalline transition metal oxide including CeO2, and TiO2. Such stable, highly crystalline nanoporous materials are desirable for catalysis and many other applications. For example, TiO2-supported gold nanoparticles are an important new class of catalysts for low temperature oxidation. The new mesoporous crystalline TiO2 or CeO2-supported gold nanoparticles showed high reactivity and on-stream stability towards low-temperature CO oxidation even after treatment at 400°C to 500°C. In our study the gold nanoparticles were directly deposited onto the mesoporous crystalline TiO2 or CeO2 via deposition-precipitation methods and then subjected to heat treatment of different temperatures. The 400°C-aged Au/mesoporous metal oxide catalyst, remains very active, achieving 50% conversion (T50 value) around -45°C, which is comparable to T50 values of as-synthesized sample. Even 500°C-aged Au/ mesoporous metal oxide is still quite active and has a T50 value as low as -24°C. As a comparison, gold supported on standard TiO2 P25 and commercial CeO2 prepared under the same condition and calcined at 500°C has a much higher T50 value. Stability tests showed that high temperature-aged Au/mesoporous TiO2 or CeO2 catalyst can maintain its activity at 28 °C over an extended period of time (i.e. 24 hr).