L. E. Makovsky

TL;DR: The model hydrodesulfurization catalysts studied in this article contained 1-30% MoO/sub 3/ on δ-gamma-alumina and were calcined at 400/sup 0/-700/sup 1 0/C for 1-32 hr and reduced at 500/sup 2 0 /C in hydrogen.

TL;DR: The Raman spectroscopic characterization of a set of MoO 3 Al 2 O 3 catalysts containing 3 to 25 wt% MoO3 is presented in this article.

Abstract: The Raman spectra of a series of WO3AI2O3 catalysts containing 1-30 wt-% of WO3 were investigated with respect to the effect of O2 calcination and H2OD2O exposure. These studies showed that the frequencies of bands due to surface tungstate species can be shifted reversibly by as much as 6% of their values during alternate O2 calcination and H2O exposure cycles. The exchange of 18O for l6O in the surface tungstate was also investigated with Raman spectroscopy and ion-scattering spectrometry. The results were used to assign Raman bands to fundamental vibrations of the surface tungstate and to propose a mechanism of interaction between H2O and the surface tungstate that hitherto has not been addressed for WO3AI2O3.

TL;DR: In this article, surface structural speciation of SiO/sub 2/supported Mo(VI) as a function of Mo impregnation technique, Mo loading, and hydration-calcination cycles is investigated by electron spectroscopy for chemical analysis (ESCA), ion scattering spectrometry (ISS), and laser Raman spectrography.