Liquid-phase catalytic activity of sulfated zirconia from sol-gel precursors: the role of the surface features

摘要

ZrO2-SO4 powders were prepared through a single step sol-gel reaction by modulating the conditions of the alkoxide hydrolysis and polycondensation steps. Sulfuric acid or (NH4)(2)SO4 was employed as the sulfating agent. The samples were calcined at 890 K and characterized as to phase composition crystallinity (XRD) and Surface area porosity (BET method). Surface functionalities were investigated by TGA/FTIR, FTIR, DRIFTS, and XPS analyses. The liquid-medium catalytic activity was tested in the esterification of benzoic acid to methylbenzoate. The role played by the conditions of the sot-gel reaction, in affecting the surface state and the catalytic properties of the powders, is discussed. (C) 2004 Elsevier Inc. All rights reserved.