A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustio...A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustion under loose contact condition.XRD and STEM mapping results confirm that all the secondary metal cations have entered the lattice matrix of tetragonal rutile SnO2 to form non‐continuous solid solutions,thus impeding crystallization and improving the surface areas and pore volumes of the modified catalysts.In comparison with regular SnO2 nanoparticles,the 3DOM SnO2 displays evidently improved activity,testifying that the formation of the 3DOM structure can anchor the soot particulates in the macro‐pores,which ensures that the contact of the soot particles with the active sites on the 3DOM skeleton is more easily formed,thus benefiting the target reaction.With the incorporation of the secondary metal cations,the activity of the catalyst can be further improved due to the formation of more abundant mobile oxygen species.In summary,these effects are believed to be the major factors responsible for the activity of the catalyst.展开更多
With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impre...With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impregnation method.By using X-ray diffraction and X-ray photoelectron spectroscopy extrapolation methods,it is disclosed that CuO disperses finely on the SnO2 support to form a monolayer with a capacity of 2.09 mmol 100 m^-2,which equals 4.8 wt%CuO loading.When the CuO loading is below the capacity,it is in a sub-monolayer state.However,when the loading is above the capacity,CuO micro-crystallites will be formed that coexist with the CuO monolayer.The soot combustion activity of the catalyst increases with the CuO loading until it reaches the monolayer dispersion capacity.A further increase in the CuO loading has no evident influence on the activity.Raman results have testified that with the addition of CuO onto the SnO2 support,a surface-active oxygen species can be formed,the amount of which also increases significantly with the increase in the CuO loading until it reaches the monolayer dispersion capacity.Increasing the CuO loading further has no evident impact on the amount of surface oxygen.Therefore,an apparent monolayer dispersion threshold effect is observed for soot combustion over CuO/SnO2 catalysts.It is concluded that the amount of surface-active oxygen sites is the major factor determining the activity of the catalyst.展开更多
基金the Natural Science Foundation of China(21567016,21503106)the Natural Science Foundation of Jiangxi Province(20171BAB213013)+3 种基金the Education Department Foundation of Jiangxi Province(KJLD14005)National Key Research and Development Program of China(2016YFC0209302)the Innovation Fund Designated for Graduate Students of Jiangxi Province(YC2015-B017)the Innovation Fund Designated for Undergraduate Students of China(201701035)~~
文摘A series of three‐dimensionally ordered macroporous(3DOM)SnO2‐based catalysts modified by the cations Ce4+,Mn3+,and Cu2+have been prepared by using a colloidal crystal templating method and tested for soot combustion under loose contact condition.XRD and STEM mapping results confirm that all the secondary metal cations have entered the lattice matrix of tetragonal rutile SnO2 to form non‐continuous solid solutions,thus impeding crystallization and improving the surface areas and pore volumes of the modified catalysts.In comparison with regular SnO2 nanoparticles,the 3DOM SnO2 displays evidently improved activity,testifying that the formation of the 3DOM structure can anchor the soot particulates in the macro‐pores,which ensures that the contact of the soot particles with the active sites on the 3DOM skeleton is more easily formed,thus benefiting the target reaction.With the incorporation of the secondary metal cations,the activity of the catalyst can be further improved due to the formation of more abundant mobile oxygen species.In summary,these effects are believed to be the major factors responsible for the activity of the catalyst.
基金supported by the National Natural Science Foundation of China(21567016,21666020)the Natural Science Foundation of Jiangxi Province(20181ACB20005,20171BAB213013,20181BCD40004,20181BAB203017)+2 种基金the Innovation Fund Designated for Graduate Students of Jiangxi Province(YC2018-B015)the Education Department Foundation of Jiangxi Province(KJLD14005)the Opening Fund of Key Laboratory of Process Analysis and Control of Sichuan Universities(2017002)~~
文摘With the objective to investigate the structure-reactivity relationship of CuO/SnO2 and eventually design more applicable catalysts for soot combustion,catalysts with different CuO loadings have been prepared by impregnation method.By using X-ray diffraction and X-ray photoelectron spectroscopy extrapolation methods,it is disclosed that CuO disperses finely on the SnO2 support to form a monolayer with a capacity of 2.09 mmol 100 m^-2,which equals 4.8 wt%CuO loading.When the CuO loading is below the capacity,it is in a sub-monolayer state.However,when the loading is above the capacity,CuO micro-crystallites will be formed that coexist with the CuO monolayer.The soot combustion activity of the catalyst increases with the CuO loading until it reaches the monolayer dispersion capacity.A further increase in the CuO loading has no evident influence on the activity.Raman results have testified that with the addition of CuO onto the SnO2 support,a surface-active oxygen species can be formed,the amount of which also increases significantly with the increase in the CuO loading until it reaches the monolayer dispersion capacity.Increasing the CuO loading further has no evident impact on the amount of surface oxygen.Therefore,an apparent monolayer dispersion threshold effect is observed for soot combustion over CuO/SnO2 catalysts.It is concluded that the amount of surface-active oxygen sites is the major factor determining the activity of the catalyst.
