Preparation of binary washcoat deposited on cordierite substrate for catalytic applications

The deposition of binary M–ZrO2 (M = Al2O3, SiO2 or TiO2) as secondary support on cordierite substrate by dip-coating was investigated and the as-prepared M–ZrO2/cordierite was characterized by means of XRD and SEM techniques. After two successive dip-coating processes, the highest washcoat loading of 25.1% was achieved in Al2O3–ZrO2/cordierite, followed by 18.7% in TiO2–ZrO2/cordierite and then 17.4% in SiO2–ZrO2/cordierite. The optimal parameters to prepare Al2O3–ZrO2 washcoat on cordierite were investigated in detail. After introduction of noble metal active components (Rh and Pd) to the secondary support, the obtained Rh/M–ZrO2/cordierite and Pd/M–ZrO2/cordierite were further tested as monolithic catalysts for the decomposition of nitrous oxide and the deep oxidation of benzene, respectively.