Supported oxorhenate catalysts prepared by thermal spreading of metal Re0 for methanol conversion to methylal

TiO2-anatase and SiO2 supported oxorhenate catalysts were prepared by an original and simple technique based on the oxidative dispersion of metallic rhenium under dry conditions. The dispersion process of the supported oxorhenate phase as a function of the rhenium coverage and the support properties are discussed on the base of in situ characterization. The structures of the as prepared catalysts were found to be comparable to those of materials prepared using the incipient wetness impregnation technique. The absence of water in the preparation technique has made it possible to highlight the role of the hydration level on the rhenium oxide volatilization. The as-prepared Re/TiO2 catalysts were found to be effective for the direct conversion of methanol to methylal.

Graphical AbstractEvolution of the 900–1000 cm−1 region of the Raman spectrum of a mixture of metal rhenium with anatase TiO2 K03 upon heating in pure O2.Figure optionsDownload as PowerPoint slideHighlights
► Supported rhenium catalysts can be easily prepared from metal Re.
► This dry process is mainly a CVD immediately followed by rhenium deposition.
► Hydration of the oxorhenate phase is dependent on the support.