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
- Bassou B, Guilhaume N, Lombaert K, Mirodatos C, Bianchi D (2010) Experimental microkinetic approach of the catalytic oxidation of diesel soot by ceria using temperature-programmed experiments. Part 1: impact and evolution of the ceria/soot contacts during soot oxidation. Energy Fuel 24:4766–4780CrossRefGoogle Scholar
- Sayle T, Parker S, Catlow RC (1992) Surface oxygen vacancy formation on CeO2 and its role in the oxidation of carbon-monoxide. J Chem Soc Chem Commun:977–978Google Scholar
- Wierzbicka A, Nilsson PT, Rissler J, Sallsten G, Xu YY, Pagels JH, Albin M, Österberg K, Strandberg B, Eriksson A, Bohgard M, Bergemalm-Rynell K, Gudmundsson A (2014) Detailed diesel exhaust characteristics including particle surface area and lung deposited dose for better understanding of health effects in human chamber exposure studies. Atmos Environ 86:212–219CrossRefGoogle Scholar