Preparation of high porous Pt–V2O5–WO3/TiO2/SiC filter for simultaneous removal of NO and particulates

The macro-porous TiO2 film was coated on the pore surface of SiC filter element using the solution of the preformed TiO2 particles (P25). TiO2-coated SiC filter element was used to prepare V2O5–WO3–TiO2/SiC catalytic filters and discussed their performances for NO reduction. The macro-porous TiO2 film showed the good catalyst support for the catalyst of NO SCR (selective catalytic reduction). The effect of solution modification with polymers such as polyethylene glycol (PEG), polyvinyl alcohol (PVA), and hydroxypropyl cellulose (HPC) was investigated on the formation of macro-porous pores. The mean pore size of TiO2 film increased slightly when some amounts of PEG, PVA, and HPC were added in the coating solution. That is, TiO2 film of the pore size larger than 40 nm was preferably formed by the addition of polymers. However, total BET area and TiO2 loading decreased relatively with the polymer addition. The increase of macro-porosity by using the polymers was not directly related with the considerable promotion for SCR activity of the catalytic filter. The additive effects Pt over the V2O5–WO3–TiO2/SiC based catalytic filters are measured and discussed. It was observed that the addition of Pt shifts the optimum working temperature for NO reduction toward the low one.