In this work,silica-alumina mixed oxides with different SiO_(2)contents(5%and 30%)were adopted as acidic supports for platinum catalysts for soot oxidation.The obtained catalysts were hydrothermally aged in 10%H_(2)0/...In this work,silica-alumina mixed oxides with different SiO_(2)contents(5%and 30%)were adopted as acidic supports for platinum catalysts for soot oxidation.The obtained catalysts were hydrothermally aged in 10%H_(2)0/air at 750℃for 20 h.The catalysts were characterized by X-ray diffraction(XRD),N_(2)adsorption,inductively coupled plasma(ICP),CO chemisorption,NH3temperature-programmed desorption(TPD),infrared(IR)spectroscopy of CO adsorption,temperature-programmed oxidation(TPO)of NO,and TPD of NO_(x).The surface acidity of catalyst was positive correlated with the content of SiO_(2),which kept platinum in metallic and partially oxidized states in an oxidizing atmosphere.Compared with sulfation treatment on the alumina support,the application of SiO_(2)-Al_(2)O_(3)mixed oxides does not result in the coverage of Pt active sites and the prepared catalysts exhibit excellent activity for NO oxidation.They promote NOxpreferential adsorption on soot and decomposition of surface oxygenated compounds(SOCs)as the sulfated Pt/Al_(2)O_(3)catalyst does.展开更多
基金financially supported by the National Key R&D Program of China(No.2017YFC0211102)the National Natural Science Foundation of China(No.21906091)the Mobile Source Emission Control Technology(No.NELMS2020A08)。
文摘In this work,silica-alumina mixed oxides with different SiO_(2)contents(5%and 30%)were adopted as acidic supports for platinum catalysts for soot oxidation.The obtained catalysts were hydrothermally aged in 10%H_(2)0/air at 750℃for 20 h.The catalysts were characterized by X-ray diffraction(XRD),N_(2)adsorption,inductively coupled plasma(ICP),CO chemisorption,NH3temperature-programmed desorption(TPD),infrared(IR)spectroscopy of CO adsorption,temperature-programmed oxidation(TPO)of NO,and TPD of NO_(x).The surface acidity of catalyst was positive correlated with the content of SiO_(2),which kept platinum in metallic and partially oxidized states in an oxidizing atmosphere.Compared with sulfation treatment on the alumina support,the application of SiO_(2)-Al_(2)O_(3)mixed oxides does not result in the coverage of Pt active sites and the prepared catalysts exhibit excellent activity for NO oxidation.They promote NOxpreferential adsorption on soot and decomposition of surface oxygenated compounds(SOCs)as the sulfated Pt/Al_(2)O_(3)catalyst does.
