Structural relationships in the low-temperature evolution of V2O5–MoO3 catalysts

Abstract

The stability of V₂O₅–MoO₃ catalysts containing up to 53 mol% MoO₃ has been investigated with electrical conductivity measurements and X-ray powder diffraction. The samples were obtained by the fusion of oxides and stored in an oxygen-free atmosphere. Subsequently their stability at room temperature was determined in air. It was found that in an oxygen-free atmosphere epitaxial layers of V₂MoO₈ intermediate phase are formed on the best developed MoO₃/V₂O₅ solid solution surface (001). The orientation of the epitaxial layer with repect to (001) depends on the chemical composition of the catalyst and also determines the stability of this catalyst at room temperature in air.