Study on hydrothermal deactivation of Pt/MnO x -CeO2 for NO x -assisted soot oxidation: redox property, surface nitrates, and oxygen vacancies
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The study mainly focuses on surface properties to investigate the deactivation factors of Pt/MnO x -CeO2 by H2 temperature-programmed reduction, CO chemical adsorption, NO x -temperature-programmed desorption (TPD), O2-TPD, NO temperature-programmed oxidation, SEM, TEM, in situ diffuse reflectance infrared Fourier transform spectra, Raman, and thermogravimetric methods. The results show that there are three main factors to lead to hydrothermal deactivation of the catalyst: redox property, oxygen vacancy, and surface nitrates. The loss of oxygen vacancies decreases the generation and desorption of active oxygen and that of surface nitrates weakens the production of NO2 and surface peroxides (-O2−). These factors greatly result in the damage of the C-NO2-O2 cooperative reaction.
KeywordsSoot oxidation Hydrothermal aging Deactivation Surface nitrates Oxygen vacancies
This study was financially supported by the National High Technology Research and Development Project of China (No. 2015 AA034603) and Science and Technology Project of Chengdu (No. 2015-HM01-00067-SF).
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