Polyoxometalates-aerogel composites for biofuel production and simple oxidation reaction -

Abstract

Nowadays, there is a rising demand for new materials with large specific surface areas to be used in many research fields such as adsorption, chromatography, catalysis, sensor technology, energy storage devices, and gas storage. An aerogel, a dried gel, is an example of these materials that exhibits exceptionally high relative pore volume and surface area. Polyoxometalates (POMs) are a colossal class of nano-sized oxygen bridged multitransitional metal clusters characterized by a daunting structural variety, resulting in different dimensions, shapes, charge density, and surface reactivity. Known to be green and efficient catalysts, POMs were previously investigated in homogeneous and heterogeneous catalysis of many reactions where high activities were reported. In order to depict the catalytic activity of polyoxometalates in homogeneous medium, transesterification of Afia corn oil will be performed using phosphomolybdic acid hydrate catalyst. After obtaining the optimal reaction conditions, the catalyst will be tested on waste used Afia corn oil. In addition, we managed to synthesize titania and silica aerogels using low-temperature traditional sol-gel chemistry followed by supercritical drying. The titania aerogels were prepared using methanol and the surface area obtained was higher than what was previously reported in literature. Furthermore, a method developed by Al-Oweini et al. was used to immobilize POMs onto the pre-synthesized silica and titania aerogels. In addition, POMs were added to the synthesized alco-gel and were incorporated into the aerogels after being supercritical dried. The structural, textural, and morphologic characterization of these materials was performed before and after immobilization and incorporation of POMs. The obtained surface area of the aerogels that were incorporated with POMs was much bigger than the surface area of aerogels functionalized with POMs. Finally, the catalytic activity of these clusters in homogeneous and heterogeneous catalysis of methyl phenyl sulfide oxidatio