Spectroscopic and Microscopic Characterization of Iron- and/or Manganese-Promoted Sulfated Zirconia

摘要: The structures of iron-promoted sulfated zirconia (FSZ), manganese-promoted (MSZ) and iron- (FMSZ) were investigated by ultra-violet-visible (UV-vis) diffuse reflectance, ESR, laser Raman, X-ray photoelectron (XP) spectroscopies transmission electron microscopy with energy dispersive microanalysis. bulk structure tetragonal the surface sulfate SZ remained virtually unchanged when promoters added to SZ, as shown Raman spectroscopy. UV-vis spectra show that iron was present in aggregated not atomically isolated species. identify these dispersed Fe2O3, micrographs confirm presence particulate on surfaces FSZ FMSZ, but MSZ. XP provide confirming evidence Fe3+, consistent ESR Fe3+ions a broad distribution coordination environments. Fe2O3is agreement results J. E. Tabora R. Davis (J. Chem. Soc. Faraday Trans.91, 1825 (1995)), whose Fe-edge extended absorption fine showed lack Fe–Zr Fe–Fe contributions, oxide clusters inconsistent zirconia. Manganese MSZ FMSZ is identified Mn2+, resolved hyperfine indicating part Mn2+ions highly still unknown locations FMSZ. are sufficient establish nature promoter effects or resolve interactions between Mn Fe indicated catalyst performance data (F. C. Langeet al., Catal. Lett.41, 95 (1996)), showing much more active than either for isomerization ofn-butane.