Catalysis Letters

, Volume 86, Issue 4, pp 151–156

The Locus of Sulfate Sites on Sulfated Zirconia

  • Rachel Marcus
  • Ulrike Diebold
  • Richard D. Gonzalez
Article

DOI: 10.1023/A:1022680421726

Cite this article as:
Marcus, R., Diebold, U. & Gonzalez, R.D. Catalysis Letters (2003) 86: 151. doi:10.1023/A:1022680421726

Abstract

The surface of sulfated zirconia was probed using X-ray photoelectron spectroscopy. It was observed that the entire inventory of sulfur could be completely removed by sputtering the surface using an argon beam. Calibration using a TiO2(110) standard resulted in a surface concentration of 2.85 sulfur atoms/nm2. This is in reasonable agreement with a value of 4.15 sulfur atoms/nm2 based on sulfur analysis on the assumption that all of the sulfur was located at the surface. These results suggest that most, if not all, of the sulfur is near or at the surface. When charging was taken into account, we observed that the oxidation state of sulfur did not change following catalyst deactivation during the isomerization of n-butane. We also determined that the entire inventory of sulfur was present as SO42-. These results reinforce previous studies suggesting that catalyst deactivation occurs as the result of carbon deposition and not a change in the oxidation state of sulfur.

sulfated zirconiaX-ray photoelectron spectroscopysulfur

Copyright information

© Plenum Publishing Corporation 2003

Authors and Affiliations

  • Rachel Marcus
    • 1
  • Ulrike Diebold
    • 2
  • Richard D. Gonzalez
    • 1
  1. 1.Department of Chemical EngineeringTulane UniversityNew OrleansUSA
  2. 2.Department of PhysicsTulane UniversityNew OrleansUSA