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MATERIALS ENGINEERING

SEMINAR

“First Principle Study for NO Oxidation in Perovskite Oxide”

By

Pilsun Yoo

Purdue MSE Ph.D. Preliminary Exam

Advisor: Peilin Liao

ABSTRACT

Among composition of emission gas, NO_x (x = 1, 2) is abundant and environmentally damaging molecule with operation of diesel engines which is associated with acid rain, smog, and ozone depletion. To decompose NO_x (x = 1, 2), Pt-based catalyst demonstrated highest conversion rate for NO_x decomposition in NO_x storage and reduction (NSR) process. Recently, La based perovskite comes into the spotlight for an alternative catalyst due to several disadvantages of Pt-based catalyst such as high cost, thermal instability, aging effect and surface oxidation under operation condition. The NO oxidation property of La based perovskite catalysts was observed to be highly dependent on different transition metals in B site and substitution of La in LaBO₃. In particular, it was noted that the oxygen vacancies driven by substitution and doping of other elements were related to the conversion rate. However, the role of oxygen vacancies on NO oxidation process was not explicitly known in previous studies. In this regard, understanding the reaction mechanism should precede to further suggest promoted and optimized alternative catalysts. This study will make it possible to suggest optimized compositions based on the understanding on the mechanism related to lattice oxygen vacancies.

Date: Monday, December 4, 2017

Time: 9:30 A.M.

Place: HAMP 2123