Graphene Oxide as Support for the Immobilization of Phosphotungstic Acid: Application in the Selective Oxidation of Benzyl Alcohol

Abstract

Graphene oxide functionalized with gama-aminopropyltriethoxysilane, is used as support for the immobilization of homogeneous heteropoly phosphotungstic acid. It is synthesized and characterized by SEM, XPS, XRD, 31P NMR and Raman. The effects of catalyst parameters and reaction conditions on the oxidation reaction of benzyl alcohol are systematically investigated. Under optimal conditions, the catalyst exhibit remarkably enhanced catalytic activity (conversion 76 % and selectivity 99 %). And the catalyst could be separated conveniently. Moreover, the loss of PW12O40 3− anion from the support under the reaction conditions is responsible for the deactivation of the catalyst. SEM images of a GO, b GO–N, c GO–N–PW (inset XPS spectrum of carbon), d GO–N–PW reused (inset XPS spectrum of carbon). The mechanism of deactivation was testified using the SEM images and the XPS spectrums in c (inset) and d (inset) .