Effect of catalyst structure on the rate of alkane oxidation over platinum

✍ Scribed by R.F. Hicks; H. Qi; M.L. Young; R.G. Lee; W.J. Han; A.B. Kooh

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 518 KB
• Volume: 45
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(90)80154-7

✦ Synopsis

The effect of catalyst structure on the intrinsic activity of platinum for methane and heptane oxidation has heen determined. The reactions were carried out in 5% excess oxygen and at low conversion.

Depending on the support and method of catalyst preparation, the platinum may be distributed between a dispersed and a crystalline phase. These phases show characteristic absorbances at 2067 and 2085 cm-', respectively, in the infrared spectrum of adsorbed carbon monoxide. These phases catalyze methane oxidation at different rates. The turnover frequency for methane oxidation at 608 K is between 0.001 and 0.01 s-' for the dispersed platinum and between 0.05 and 0.10 s-t for the crystalline platinum. The turnover frequency for heptane oxidation is insensitive to the platinum phase present, and varies from 0.003 to 0.011 s-t at 413 K. For platinum dispersions ranging from 6 to lOO%, the specific activities for methane and heptane oxidation are not significantly affected by crystallite size.