(258c) Supported Gold Catalysts Decorated with Ti-Oxo Clusters of Different Nuclearity in the Selective Oxidation of Propane in the Presence of H2 and O2

Effective selective oxidation of light alkanes could provide a promising one-step production of valuable chemicals at low costs, and significantly attenuate the burdens on the environments compared with other oxidation processes. However, the studies in supported gold catalysts in the selective oxidation of propane are only recent and little is known. Ti-containing supports have been widely used in catalysis. Propene is selectively produced over Au/TiO₂,¹ while acetone and isopropanol are the main products over Au/TS-1.^2,3 Although Ti-OOH is generally accepted as the reaction intermediate resulting from the reaction of active Ti sites and H₂O₂ formed on Au, the fundamentals of altering the selectivity over TiO₂ versus TS-1 are not clear. In light of their structures and acid/base properties, we hypothesize that nuclearity of Ti-oxo clusters could play an important role in changing selectivity. We have prepared Ti-oxo complexes of different nuclearity (one to four) and deposited them onto Au particles. The Ti-oxo complexes and the decorated Au catalysts were characterized by NMR, EXAFS, and TEM. Results of characterization and catalysis with these Ti-modified Au catalysts in propane selective oxidation are presented.  

1 J. J. Bravo-Suárez, K. K. Bando, J. Lu, T. Fujitani and S. T. Oyama, J. Catal., 2008, 255, 114.

2 J. J. Bravo-Suarez, K. K. Bando, T. Fujitani and S. T. Oyama, J. Catal., 2008, 257, 32.

3 J. J. Bravo-Suarez, K. K. Bando, T. Akita, T. Fujitani, T. J. Fuhrer and S. T. Oyama, Chem. Commun., 2008, 3272.