Superior thermal stability and oxygen storage capacity of ceria nanoparticles dispersed on alumina cryogel

Cerium-dispersed alumina cryogel was prepared from cerium nitrate and aluminum sec-butoxide by a combination of one-pot sol-gel with freeze drying. The cryogel catalyst exhibited higher thermal stability of ceria and larger oxygen storage capacity than the corresponding xerogel and impregnation catalysts. The better stability and capacity were owing to the homogeneous distribution of cerium in boehmite gel by the one-pot synthesis of cerium-boehmite gel, and also to the suppression of aggregation of the cerium during the subsequent elimination of water from frozen gel by sublimation. As a result, cerium was finely dispersed and stabilized throughout the alumina cryogel, retarding the sintering of ceria at high temperatures. The destruction of fine structures of the catalyst at high temperatures was less pronounced on the cryogel, which also contributed to the stability of ceria.