Mesoporous ceria-zirconia solid solutions as oxygen gas sensing material using high temperature hot plates

Abstract

Mesoporous ceria and ceria-zirconia solid solutions have been synthesized following a route based on the use of silica hard template. Two different structures have been selected, one based on a three dimensional gyroidal structure, named KIT6, and other based on a two dimensional layered structure named SBA15. The presence of zirconium in the ceria sub lattice enhances the capability to transform Ce+4 to Ce+3 such as it is proved from the thermogravimetry measurements that show a large increase of the oxygen storage capacity. Ce(1-x)ZrxO2 solid solutions prepared making replicas of previously synthesized mesoporous silica have been characterized and tested under different oxygen-containing atmospheres at sensing temperatures above 500oC with oxygen variation between 1% to 100% of oxygen. This binary compound oxide present a variation of its electrical conductivity with the oxygen partial pressure that follow a potential law R=Ro[O2]1/n with n = 4 corroborating that the sensing mechanism is dominated by electronic conductivity processes related to the contribution of the Ce+3. Therefore, these high stable mesoporous materials with high active surface become a promising candidate as oxygen sensing materials for gas sensing hotplate platforms.