Mesostructured Zirconium Oxide
AbstractThe supramolecular templating technique was used to synthesize both hexagonal (Hx- ZrO2) and lamellar (L-ZrO2) phases of zirconium oxide. Under the conditions used in this work, the use of long chain primary amines and quaternary ammonium surfactants resulted in the exclusive formation of lamellar and hexagonal phases, respectively. The use of long chain cetyldimethylamine afforded a mixture of a hexagonal and a lamellar phases. Effects of synthesis parameters such as the ZrO2/surfactant ratio, ZrO2/water ratio, the nature of surfactant, the crystallization temperature and time on the formation of mesostructured ZrO2 were also studied. Addition of 1,3,5-trimethylbenzene (TMB) as a swelling agent led, in the presence of cetyltrimethylammonium bromide, to the formation of a lamellar phase rather than to pore enlargement. These materials were characterized by XRD, FTIR, XPS and EDX techniques. Regardless of their structure, the as-synthesized materials collapsed upon calcination. Treatment with monobasic potassium phosphate followed by calcination at 350 °C led to the formation of a stable porous Zr–P oxide with a surface area as high as 540 m2/g.
Synthesis and Physical Properties of Long Chain Compounds. X. Studies on the X-Ray Diffraction Patterns of Normal Higher Primary Amines