MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffra...MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffraction（XRD）,Brunauer-Emmett-Teller（BET）,X-ray photoelectron spectroscopy（XPS）,Raman,O2 temperature-programmed desorption（O2-TPD）,H2 temperature-programmed reduction（H2-TPR） and NO temperature-programmed oxidation（NO-TPO）.The MnOx-CeO2 solid solutions did not form without any calcination process.The oxidation state of manganese tended to increase while the ionic valence of cerium decreased in the mixed oxides,accompanied with the formation of oxygen vacancies.This long-ranged electronic interaction occured more significantly in the tight-contact mixture of MnO and CeO2.The formation of more Mn4＋and oxygen vacancies promoted the catalytic oxidation of NO in an oxygen-rich atmosphere.展开更多
基金supported by National Natural Science Foundation of China(51072096)National Basic Research Program of China(2010CB732304)National High-Tech Research and Development Program of China(2013AA065302)
文摘MnO and CeO2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides,respectively.The monoxides and their physical mixtures were characterized by X-ray diffraction（XRD）,Brunauer-Emmett-Teller（BET）,X-ray photoelectron spectroscopy（XPS）,Raman,O2 temperature-programmed desorption（O2-TPD）,H2 temperature-programmed reduction（H2-TPR） and NO temperature-programmed oxidation（NO-TPO）.The MnOx-CeO2 solid solutions did not form without any calcination process.The oxidation state of manganese tended to increase while the ionic valence of cerium decreased in the mixed oxides,accompanied with the formation of oxygen vacancies.This long-ranged electronic interaction occured more significantly in the tight-contact mixture of MnO and CeO2.The formation of more Mn4＋and oxygen vacancies promoted the catalytic oxidation of NO in an oxygen-rich atmosphere.
