Synthesis of ZrO2-SiO2 mesocomposite with high ZrO2 content via a novel sol-gel method

A novel, convenient, one step sol-gel technique using sodium silicate and carbonate complex of zirconium in basic medium leads to the synthesis of mesostructured zirconia-silica composite with narrow pore size distribution having moderately high surface area (360-500 m2/g). These materials were characterized by powder low angle X-ray diffraction (XRD), N2 sorption isotherms, HRTEM, 29Si-MAS NMR, and FTIR. The surface acidity of the composites has been analyzed through FTIR spectra of pyridine-adsorbed compounds. Nitrogen adsorption data, HRTEM and XRD patterns confirmed that, the structure, high surface area, and uniform pore size distribution are maintained in the synthesized composites with Si/Zr ratio of 2 to 0.5. Further increase in silica loading showed the reduction of surface area. EDX analyses show that this novel sol-gel technique efficiently avoids the leaching of zirconium and silica from the framework of the material. The calcined ZrO2-SiO2 mesocomposite show worm-like pores in the microstructure and have both Brönsted and Lewis acid sites.