Synthesis and functional verification of the unsupported active phase of V xO y catalysts for partial oxidation of n-butane

Abstract

We studied unsupported V x O y nanoparticles prepared by a novel nonaqueous route in the selective oxidation of n-butane to maleic anhydride. The evolution of the electronic and geometric structure of the material was characterized by X-ray photoemission spectroscopy, electron energy-loss spectroscopy, transmission electron microscopy, and electron diffraction before and after the reaction at different temperatures. A change from a water-mediated C C bond cracking functionality of the catalyst forming acetic acid to an oxidizing functionality resulting in maleic anhydride was observed. It was found that the particles underwent a radical modification of the geometric and electronic structure that finally resulted in V 2O 5 crystals. Experimentally derived conclusions are related to some conceptual claims from the literature.