Interactions of molybdenum oxide with various oxide supports: Calcination of mechanical mixtures

• Published in: Journal of catalysis 1987-06, Vol.105 (2), p.445-454
• Main Authors: Stampfl, Sharon R., Chen, Yi, Dumesic, J.A., Niu, Chunming, Hill, C.G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Catalysis; Catalysts: preparations and properties; Catalytic reactions; Chemistry; Exact sciences and technology; General and physical chemistry; General. Nomenclature, chemical documentation, computer chemistry; Other techniques and industries; Theory of reactions, general kinetics; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/0021-9517(87)90072-8

Laser Raman and Fourier transform infrared spectroscopies as well as X-ray diffraction were used to study the interactions of MoO 3 with various metal oxide supports. Intimate mechanical mixtures containing an amount of MoO 3 corresponding to less than a monolayer were calcined at 720 K. In the cases where the supports were TiO 2, SnO 2, Al 2O 3, and MgO surface molybdate species were formed on calcination via thermally induced spreading of the bulk MoO 3 phase. Interactions between the support and the MoO 3 were sufficiently strong in these cases that no bulk MoO 3 could be detected in the calcined mixture. A weaker interaction occurs in the case of SiO 2. Raman results from the calcined MoO 3 TiO 2 mixture agree with spectra obtained from catalysts prepared by equilibrium adsorption and incipient wetness impregnation; the nature of the surface molybdate species is relatively independent of the preparation method.