NMR and IR Study of the Protonated Species on the Surface of Scandia
IR spectra of polycrystalline Sc2O3 degassified above 500°C show bands at 3680 and 3665 cm−1, of isolated surface hydroxyls. Samples of gels treated up to 400°C present a wide zone of IR absorption, due to molecular adsorbed water and hydroxyls tied through hydrogen bonds. NMR spectra can separate the narrow band of molecular water from a wider one of H-bonded OH groups. From the linewidth of this band- 3–6 G due to the high nuclear magnetic moment of scandium- conclusions can be obtained about the different types of surface OH and the evolution of its surface population with the dehydroxylation treatment, thus clarifying the complex situation deduced from previous IR, TGA experiments.
KeywordsHydroxyl Catalysis Dehydration Chemisorption Scandium
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