A Novel Fluidized Bed Technique for Measuring UV Raman Spectra of Catalysts and Adsorbates

A novel “fluidized bed” (FB) technique for measuring UV Raman spectra of catalysts and adsorbates has been developed to minimize thermal degradation and possible photodecomposition of adsorbates by UV radiation. UV Raman spectra were measured for naphthalene, benzene, and pyridine adsorbed in zeolite H-USY. When measurements were performed on samples in the form of a stationary or spinning disc, the Raman spectra show the presence of “coke,” a typical end product of heating and photochemistry. In contrast, the Raman peaks of the unreacted adsorbates dominate spectra measured using the FB apparatus. An in situ FB reactor was constructed and the UV Raman spectrum of n-heptane in zeolite H-ZSM-5 was measured. These results indicate that the FB technique is a promising method for measuring UV Raman spectra of catalysts and adsorbates.