FT-IR/PA Study of Quinoline Adsorbed on Calcined and Sulfided Mo/Gamma-Al2O3

摘要

Photoacoustic infrared spectra of quinoline adsorbed on gamma-alumina and on oxide and sulfided forms of Molybdenum/gamma-alumina are reported. In agreement with prior studies with pyridine, both Lewis and Bronsted acidic sites are detected on the oxide catalyst, but only Lewis sites are observed on the sulfided catalyst. Certain surface hydroxyl groups and some Lewis site Al3+ anionic vacancies appear to participate cooperatively in the binding of quinoline to the sulfided Molybdenum/gamma-alumina surface. A precursor to carbonium ions that does not involve a Bronsted acid site is postulated.