Synthesis and characterization of nanostructured sulfated zirconias

Thermally stable sulfated zirconia catalysts were synthesized via a new templating procedure and compared with standard zirconia materials prepared by precipitation without templates. Two preparation routes with various amphiphilic systems were employed as structure directing agents: (1) synthesis with hexadecyltrimethylammonium bromide, and (2) combined use of surfactant Brij-56® and triblock-copolymer Pluronic P123®. The formation of materials was characterized by TEM, SEM, X-ray diffraction as well as nitrogen adsorption and mercury intrusion techniques. Different self-assembling properties of the structure directing compounds led to sulfated zirconia materials exhibiting improved morphological and structural properties in terms of thermal stability, specific surface areas, pore diameters and porosity factors. Notably, hierarchical pore structures were obtained for the synthesis route via a combined use of Brij-56® and P123®. Moreover, the morphological features of these materials were evidenced by a significantly improved isomerization activity of n-butane.