Reactivity of Platinum Hydrides in the Selective Hydrogenation of Acetic Acid on Pt-ReOx/TiO2 Catalysts

摘要

The interaction between hydrogen and subnanometer deposited Pt-ReOx particles active in dehydrogenation of carboxylic acids is investigated via in situ diffuse reflectance IR spectroscopy. Absorption bands of platinum hydrides are detected in the range of 2025-2043 cm(-1), and their high reactivity with respect to adsorbed acetic acid is revealed. The absorption band of platinum hydride shifts toward higher frequencies and becomes more intense, due to the effect of adjacent acetates on the electron state of platinum. It is established that in a hydrogen medium the intensity of platinum hydride bands sharply increases after the adsorption of acetic acid and then gradually decreases owing to the reaction of the hydrides with surface acetates.