Supported WOx-based catalysts for methanol dehydration to dimethyl ether

TiO2-supported WOx solids with different W loadings (between 0.2 and 9.0 at. W nm−2) were prepared by incipient wetness impregnation of TiO2 with ammonium (para)tungstate aqueous solutions. The prepared materials were characterized in detail by inductively coupled plasma emission spectrometry (ICP-OES), N2 adsorption-desorption isotherms, X-ray diffraction (XRD), temperature-programmed desorption of NH3, X-ray photoelectron and Raman spectroscopy, and infrared spectroscopy using CO and pyridine as probe molecules. We have observed that the molecular structure of WOx species and their acid features are markedly influenced by the W surface density. A relationship between catalytic performance in dimethyl ether formation via methanol dehydration and the acid properties is found.