Catalytic Conversion of Alcohols. Relation of Hafnium-Zirconium Mixed Oxide Catalytic Selectivity to Surface Composition Measured by Raman Spectroscopic Mehods

Article abstract of DOI:10.1021/j100306a033

The Raman spectra obtained for a series of mixed Hf-Zr oxide catalysts, prepared by coprecipitation, indicate that the surface composition is similar to the bulk composition.Hf, impregnated on calcinated zirconia, remains on the surface following calcination at 600 deg C but migrates into the bulk if calcination is effected at 1000 deg C.The catalytic selectivity abruptly changes from that of pure hafnia to that of pure zirconia at a composition corresponding to Hf:Zr = ca. 1:9 rather than that undergoing a gradual change that follows the surface composition.Surface HF may produce a significant background in the Raman spectra that increases for higher Hf compositions; the extent of the background depends upon both calcination temperature and Hf composition.