Quantum mechanical investigation of CO oxidation conducted on automotive exhaust emission catalysts containing La and Pd/La on ceria-zirconia

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2016

Öğrenci: YASEMİN KAYA

Danışman: IŞIK ÖNAL

Özet:

In this study, Three Way Catalyst (TWC) is investigated via Density Functional Theory (DFT) methods. DFT techniques are implemented by Vienna Ab Initio Simulation Package (VASP). Atomic lanthanum substituted and both palladium and lanthanum substituted CZO (110) surfaces are investigated for their catalytic activity in terms of carbon monoxide oxidation. Relative energy profiles for CO reaction mechanisms on these surfaces are obtained and activation barriers of reaction steps are analyzed by using CI-NEB method. It is observed that Oxygen Storage Capacity (OSC) of CZO is remarkably enhanced by the introduction of lanthanum to CZO and Pd-CZO structure. The catalytic activity on La-doped surface in terms of CO oxidation is found as energetically more favorable compared to Pd+La doped surface since there is no activation barrier for the reaction steps carried out on this surface.