(549a) Macroporous Mixed Movtenbox For Propane (Amm)Oxidation

Ordered porous mixed metal oxides are highly promising for applications in selective oxidation catalysis because of their tunable ?bulk? and surface compositions, variable metal oxidation states, high surface areas, as well as large and uniform pore sizes. In particular, vanadium, molybdenum, tellurium and niobium-based mixed oxide phases are very attractive for selective oxidation and ammoxidation of lower alkanes, such as propane. Mesoporous single and mixed oxides of vanadium [1], molybdenum [1], and niobium [1-4], and macroporous niobium oxide [5] have been reported. However, preparation of thermally stable ordered porous mixed multicomponent metal oxides with high surface areas still remains a challenging task.

In this work, we explored the synthesis of macroporous mixed MoVTeNbOx employing colloidal polystyrene spheres as the template. The use of this template template allows confining the synthesis of the catalytic MoVTeNbOx phases to the nanoscale region of inorganic walls (more than 20 nm) in these ordered macroporous phases in order to nucleate a desired mixed metal oxide phase and enhance thermal stability of the ordered structure. The structural and physicochemical properties of the resulting macroporous mixed MoVTeNbOx catalysts were characterized by XRD, EDS, SEM, and TEM. The catalytic performance of these novel macroporous metal oxide phases was compared with that of the conventional catalysts with similar chemical compositions reported in the literature for the model reaction of propane ammoxidation to acrylonitrile. The colloidal sphere templating method described here represents a promising synthesis approach for the design of novel mixed transition metal oxides for catalytic applications.

Acknowledgements This study was conducted with financial support of the National Science Foundation (NSF CAREER CTS-0238962 to VVG).

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