Study On Fabrication Of Perovskite Catalysts Supported On Porous Cordierite Monoliths And The Catalytic Performance For Soot Combustion

Diesel particulate filters (DPF) showed excellent performance in diesel sootremoval, but need regular regeneration. In this thesis, a cordierite monolithsurface-modified by three dimensionally ordered macroporous have been fabricatedusing colloidal crystal template of polystyrene spheres and the catalysts ofLa1-xSrxCoO3、La1-xCexMnO3supported on porous modified cordierite monolith arefabricated by impregnation-sintering method. The physic-chemical properties of thesecatalysts are characterized by SEM, EDX, XRD, FT-IR, TG-DSC and N2adsorption-desorption isotherms. The catalytic activity of these supported catalysts fordiesel soot removal studied in Thermogravimetric analyzer under the simulated dieselexhaust conditions. This study will provide some guidance for DPF used in theremoval of diesel soot. Several conclusions have been drawn:(1) Polystyrene spheres (PS) with diameters of120-150nm were synthesized byemulsion polymerization technique. The obtained PS did not aggregate and theirsize distribution was narrow. Three dimensionally ordered macroporous (3DOM)SiOC were prepared by the means of colloidal crystal template method using PSas templates. The pore diameters and the skeleton thickness of3DOM wereconcentrated in100-150nm and50-100nm, respectively.(2) The catalysts particle of La1-xSrxCoO3、La1-xCexMnO3supported on modifiedcordierite monolith are fabricated by impregnate-sintering method. The SEMresults revealed that the particle of catalysts adhere to SiOC skeleton uniformlyand the particle size distributed in30-50nm. N2adsorption-desorption isothermsresults revealed that the average pore radius of3DOM increase from26.99nm to48.11nm after several times calcination, which imply that the pore structure of3DOM collapse after calcination.(3) To simulate diesel exhaust conditions, the soot will be dispersed by alcohol andimpregnated into cordierite monolith. The TG-DSC results revealed that the10%soot conversion rate temperature (T10), the maximum rate temperature (Tm), the90%soot conversion rate temperature (T90) over the modified cordierite decreaseby27C,37C,52C respectively, compared with the bare soot; T10, Tm, T90over the catalysts supported cordierite decrease by80C,50C,55C respectively,compared with bare soot. The catalytic activity follows the following order: tightcontact> pore contact>loose contact.