Catalytic performance and the surface character of Ga2O3-supported Bi-Mo complex oxides were studied to obtain direct formation of methacrolein from isobutane. Bi2Mo3O12 (• phase) and Bi2MoO6 (γ phase) showed higher catalytic activity than Bi2Mo200 ([~ phase) for isobutane partial oxidation. Supporting Ga2O3, which is an active catalyst for dehydrogenation of hydrocarbons, onto the oxides, enhanced the catalytic activity. The optimum amount of supported Ga2O3 on Bi2Mo3O12 was ∼ 3 wt % for methacrolein formation. In the presence of oxygen, a remarkable amount of hydrogen over Ga2O3 during the isobutane oxidation but no hydrogen was formed over Ga2O3/Bi2Mo3O 12. It is confirmed from TPR that Ga2O3 and Bi2Mo3O12 were not reduced until 550°C but the reduction of Ga2O3/Bi2Mo3O 12 started at 350°-380°C. The on-set temperature in TPR of the Bi-Mo complex oxides decreased to 350°-380°C from 500°C by the supporting Ga2O3 onto the oxides, and the catalysts after TPR measurement are composed of BiO, Bi, MoO2 in addition to Bi2Mo3O12. These results suggest that the hydrogen spillover took place over supported catalyst. Ga2O3/Bi2Mo12O 12 catalyst showed higher activity and high selectivity for methacrolein at 450°C. In the non-aerobic oxidation of isobutane over the Ga2O3/Bi2Mo3O 12 catalyst, the formation rate of COx significantly reduced, and methacrolein and isobutene were selectively obtained when the reduction degree of the catalyst was < 0.3% at 450°C.
|Number of pages||9|
|Journal||Sekiyu Gakkaishi (Journal of the Japan Petroleum Institute)|
|Publication status||Published - Jan 2003|
All Science Journal Classification (ASJC) codes
- Fuel Technology
- Energy Engineering and Power Technology