In situ solid -state NMR and FTIR investigations of 2-propanol and acetone photocatalytic oxidation

Weizong Xu, Purdue University

Abstract

The photocatalysis of 2-propanol and acetone on TiO2 powder and TiO2 supported catalysts has been studied using in situ solid-state NMR and FTIR techniques. It was found that the formation of chemisorbed intermediates on the catalytic surface was the most important factor for determining efficient photooxidation. A new chemisorbed species, propylene oxide, was identified when acetone was adsorbed on a TiO2 catalyst supported on porous Vycor glass (PVG) and this intermediate is unique to that catalyst. Propylene oxide is responsible for the faster PCO rate of acetone on the TiO2/PVG catalyst compared to that using a TiO 2 powder catalyst. When 2-propanol was adsorbed on to TiO2 powder, the chemisorbed species 2-propoxide was formed, which allowed for faster oxidation of 2-propanol than on the TiO2/PVG catalyst. The morphology of the catalysts has a critical role in determining the formation of these intermediate species and thus helps determine the photocatalytic behavior. It was also found that high oxygen concentrations could increase the reaction rate of both 2-propanol and acetone, although this effect depended on the type of irradiation source used. In addition, using a pulsed UV source could change the reaction mechanism by introducing an abrupt temperature increase.

Degree

Ph.D.

Advisors

Raftery, Purdue University.

Subject Area

Analytical chemistry|Environmental science

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