Preparation of Mesoporous CeO2 with High Thermal Stability by Ammonium Carbonate Hydrolysis Method

Abstract

Two series of CeO2 materials were prepared by two different synthetic routes, i.e. the conventional ammonia precipitation route (CR) and the ammonium carbonate hydrolysis route (HA) using (NH4)(2)CO3 in the presence of hydrogen peroxide. The formation process and decomposition behavior of the precipitates were investigated by FTIR, Raman, thermogravimetric and differential thermal analysis (TG/DTA) and X-ray photoelectron spectroscopy (XPS). The results show that the as-prepared precipitate obtained by HA consists of O-2(2-), CO32- and OH- species. However, after hydrothermal digestion at 80 degrees C, the CO32- species is gradually hydrolyzed into OH- species. Although the chemical components of the digested precipitates prepared by these two routes are almost the same, the agglomeration of CeO2 particles is markedly modified. The CeO2 powder produced by HA exhibits higher thermal stability and better reduction property compared to that obtained by CR. After the heat treatment at 900 degrees C for 3 h, the CeO2 powder from HA route still remains a surface area of 27 m(2).g(-1).