Synthesis of mesoporous La2Zr2O7 with high surface area by combining epoxide-mediated sol-gel process and solvothermal treatment

Abstract

Mesoporous La2Zr2O7 was successfully prepared by combining epoxide-mediated sol-gel process and solvothermal treatment. The gelation was controlled by addition of propylene oxide to the ethanol solutions of nitrates. Solvothermal treatment was adopt to strengthen the mesopore structure and inhibit the collapse of pores during abiment pressure drying, and it obviously increased surface area. The as-synthesized mesoporous La2Zr2O7 showed nanoparticles assembling and mesoporous structure, and the nanoparticles has a surface area of 302.9 m2/g and an average pore size of 22.2 nm. The mesoporous La2Zr2O7 has an amorphous structure with some organic component. After heat treatment, the inorganic transformation occurred and it crystallized into pyrochlore structure. With increase of heat treatment temperature, the particles of mesoporous La2Zr2O7 become larger for the sintering of nanocrystalline La2Zr2O7. The surface area can retain at 92.7 m2/g after 600 °C, and decreased to 12.4 m2/g after 1200 °C for 3 h. This facile route provides a low-cost strategy for the preparation of mesoporous metal oxide with high surface area.