Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye
Tezin Onay Tarihi: 2010
Öğrenci: NUR KANDİLLİ
Danışman: IŞIK ÖNAL
Özet:In this work, slurries of powder catalysts are washcoated on 22 mm diameter and 13 mm height cordierite monoliths. CeO2-ZrO2 (CZO) and CeO2-ZrO2- Al2O3 (CZAO) mixed oxides are synthesized by co-precipitation and sol-gel methods respectively, to be used as support materials of Pd and Rh metals. Metal loaded CZO is mixed with gamma phase alumina. Powder catalysts and their slurries are characterized by XRD, BET, ICP-MS and the monolithic catalysts are imaged by SEM. Catalytic activities of monolithic catalysts are tested in dynamic test system which is computerized and basically composed of gas flow control and conditioning units, split furnace, quartz reactor, mass spectrometer and CO analyzer. Gas mixture containing CO, C3H6, C3H8, NO, H2, O2, CO2, SO2, H2O and N2 is used to simulate the exhaust gas of gasoline vehicles. O2 is oscillated at 1 Hz frequency around the stoichiometric condition. Monolithic catalyst in the reactor is heated and cooled between 150 ºC and 600 ºC. Gas composition data from massspectrometer and CO analyzer and temperature data from thermocouple at the monolith entrance, are converted to conversion versus temperature graphs. Results of 26 activity tests are compared. Catalyst containing coimpregnated CZO support material with metals, showed the lowest loss of catalytic performance after exposure to SO2 during activity tests. Catalyst containing separately impregnated CZO support material, showed the highest resistance against thermal aging at 900 ºC and 1000 ºC, and even improved catalytic activity after aging. These catalysts showed higher resistances against the applied procedures than the commercial catalyst.