Study on the Coating of Nano-particle and 3DOM LaCoO3 Perovskite-type Complex Oxide on Cordierite Monolith and the Catalytic Performances for Soot Oxidation: The Effect of Washcoat Materials of Alumina, Silica and Titania

Abstract The novel catalysts of LaCoO 3 /ɤ-Al 2 O 3 /cordierite monolith, LaCoO 3 /SiO 2 /cordierite monolith, LaCoO 3 /TiO 2 /cordierite monolith were prepared by using aluminum oxide, silicon dioxide and titanium dioxide nanoparticles as washcoat and monolithic cordierite as the monolithic ceramic substrate. The obtained samples were characterized by means of XRD, SEM, EDS, BET, and ultrasonic vibration test (Medi II Pselecta). The surface area of the cordierite monolith-supported LaCoO 3 /ɤ-Al 2 O 3 is larger than those of LaCoO 3 /SiO 2 and LaCoO 3 /TiO 2 . The coating of alumina, silica oxide and titania nanoparticles could increase the surface area of monolithic cordierite and also endue the coated layer with engineered structure. The results of thermal treatment experiment indicate that the good thermal stability of the ɤ-Al 2 O 3 coating on the cordierite. The ultrasonic vibration test results showed that the washcoat was adhered to the substrate strongly. The weight loss for the samples LaCoO 3 /ɤ-Al 2 O 3 /cordierite (the most desired preparation protocol in this study) eventually reached about 3%, which was considered as a low weight loss. The LaCoO 3 /ɤ-Al 2 O 3 /cordierite monolith catalysts were successfully prepared by coating ready-made 3DOM LaCoO 3 (perovskite-type oxides) catalysts onmonolithic cordierite substrate with a dip-coating method by employing aluminasol for the first time. The catalytic activities of a series of monolithic catalystsLaCoO 3 /ɤ-Al 2 O 3 /cordierite, LaCoO 3 /ɤ-Al 2 O 3 /cordierite (3DOM-catalysts), LaCoO 3 /SiO 2 /cordierite, LaCoO 3 /TiO 2 /cordierite were evaluated for soot combustion. Thenano LaCoO 3 /ɤ-Al 2 O 3 /cordierite catalysts gave the highest catalytic activity for soot combustion among the studied catalysts. The T 10 , T 50 , T 90 over the LaCoO 3 /ɤ-Al 2 O 3 /cordierite catalyst were 199.4 °C, 340.5 °C, 405.3 °C, respectively, and s c o 2 m was 99.9%.