First-principles study of NO oxidation on Pt/CaTiO3 interface

Abstract

A well-dispersed noble metal on perovskite support is expected to show good catalytic ability for NO oxidation under oxygen-rich conditions, which is an important step in reducing NO in lean burn exhaust gas. In this study, we investigated the catalytic oxidation of NO to NO2 on a Pt4/CaTiO3 (001) model to evaluate interfacial effect. Results showed that O2 preferred Pt–Ti interface sites, and that the decomposition of O2 required a dissociation activation barrier of 0.97eV. The decomposed O–O on the interface required nearly no activation barrier in the subsequent NO oxidation. However, the most rate-limiting step involved the desorption of the second formed NO2 from interfacial Pt4/CaTiO3 (001), which yielded a significant desorption barrier of 2.63eV. These findings can help understand the oxidation process of NO to NO2 on noble-metal–perovskite interface.