ELECTRON-OPTICAL STUDIES OF FRESH AND REDUCED VANADIUM PENTOXIDE-SUPPORTED RHODIUM CATALYSTS

One percent Rh/V2O5 catalysts prepared by wet impregnation with RhCl3 · xH2O and subsequent reduction in hydrogen were shown to be subject to the formation of lower oxides of vanadium via an Rh-catalysed reduction process. V4O9, VO2, and V2O3 compounds were observed at reduction temperatures of 250, 450, and 600°C, respectively, as characterised by IR, XRD, and electron optical methods. Maximum hydrogen uptake by the Rh-loaded V2O5 occurred at 155°C according to TPR data, and this contrasts with the onset of reduction of V2O5 alone at ∼450°C. Mechanistic and structural aspects of the Rh-catalysed reduction process are discussed. © 1993 Academic Press, Inc.