Effect of Synthetic Parameters on Structural, Textural, and Catalytic Properties of Nanocrystalline Sulfated Zirconia Prepared by Sol−Gel Technique

Abstract

A series of sulfated zirconia samples were synthesized by a two-step sol−gel technique using zirconium propoxide as a precursor having two different concentrations, hydrolyzed with aqueous ammonia at pH 9−10 and sulfated with sulfuric acid. Effects of various synthetic parameters were studied on the structural, textural, and catalytic properties, which were determined using XRD, FT-IR, DRIFT, N2 adsorption−desorption isotherms, and benzylation of toluene. The sol−gel technique resulted in the formation of nanocrystalline sulfated zirconia having a low crystallite size (<20 nm) predominantly in the tetragonal phase with a surface area and pore size ranging from 64 to 116 m2/g and 47−67 A, respectively. The amount of sulfur and the nature of the sulfur species bound with the zirconia surface were observed to play a significant role in determining the catalytic activity of a sample. Ultrasonication assisted sulfated zirconia samples prepared with a higher concentration of the metal precursor were found to be...