A potential substitution of noble metal Pt by perovskite LaCoO3 in ZrTiO4 supported lean-burn NOx trap catalysts

摘要

The support ZrTiO4 and the lean-burn NOx trap (LNT) catalyst K/LaCoO3/ZrTiO4 were prepared by co-precipitation and successive impregnation, respectively. This catalyst exhibits much better NOx storage performance than the conventional Pt-containing catalyst K/Pt/ZrTiO4. Compared with Pt, the perovskite LaCoO3 possesses higher capability for NO to NO2 oxidation, giving a higher NOx storage capacity. NOx is mainly stored as nitrate at 350 "C over K/UCoO3/ZrTiO4. Mild sulfation shows little effect on the structure and performance of this catalyst. Total substitution of Pt by perovskite LaCoO3 to lower the cost of LNT catalysts is feasible.