Mixed Ionic–Electronic Conducting Catalysts for Catalysed Gasoline Particulate Filters

Abstract

A catalyst based on Pd and Rh nanoparticles supported on a Gadolinia-Doped Ceria support, a mixed O2−/e− ionic electronic conductor (MIEC), has been prepared and washcoated in SiC catalyzed gasoline particulate filters (cGPF) prototypes. These filters have been prepared and tested for the aftertreatment of gasoline direct injection engine exhausts. Catalytic performances of various configurations of cGPFs (different catalyst loadings and locations) have been carried out near real conditions and compared with those of a commercial three-way converter TC as well as a monolith washcoated with the same MIEC-supported catalyst. Among all the samples tested, the most promising one is a GPF equipped with a SiC filtration membrane on which a catalytic layer has been washcoated. This cGPF combines good filtering efficiency, due to the membrane, and remarkable catalytic performances in presence of soot and water. The catalytic performance is greater than those of a commercial TC, in spite of a 9 times lower platinum group metal loading. This is attributed to both self-sustained electrochemical promotion and a higher availability of the active sites localized on the membrane.