α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decrease...α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.展开更多
A series of supported CeO2/TiO2 catalysts were prepared to explore the influence of CeO2 loading on these catalysts for the selective catalytic reduction of NO3 by NH3(NH3-SCR).The catalysts were investigated in detai...A series of supported CeO2/TiO2 catalysts were prepared to explore the influence of CeO2 loading on these catalysts for the selective catalytic reduction of NO3 by NH3(NH3-SCR).The catalysts were investigated in detail by means of XRD,Raman,H2-TPR,NH3-TPD,XPS,in situ DRIFTS,and NH3-SCR reaction.The activity of the catalyst is closely related to the content of CeO2.When the loading of CeO2 is near the dispersion capacity(1.16 mmol Ce4+/100 m^2 TiO2),the catalytic activity is better.This may be because that the dispersed CeO2 is the active species and the catalyst has appropriate redox property,along with the larger amounts of surface Ce content and surface adsorbed oxygen species.Finally,a possible reaction mechanism via the Langmuir-Hinshelwood(L-H)mechanism is tentatively proposed to further understand the NH3-SCR reaction.展开更多
基金supported by the National Natural Science Foundation of China(51502221)~~
文摘α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.
基金Project supported by the National Natural Science Foundation of China(21773106,21677069,51674002,21307001)the Open Project Program of Jiangsu Key Laboratory of Vehicle Emissions Control(OVEC037)。
文摘A series of supported CeO2/TiO2 catalysts were prepared to explore the influence of CeO2 loading on these catalysts for the selective catalytic reduction of NO3 by NH3(NH3-SCR).The catalysts were investigated in detail by means of XRD,Raman,H2-TPR,NH3-TPD,XPS,in situ DRIFTS,and NH3-SCR reaction.The activity of the catalyst is closely related to the content of CeO2.When the loading of CeO2 is near the dispersion capacity(1.16 mmol Ce4+/100 m^2 TiO2),the catalytic activity is better.This may be because that the dispersed CeO2 is the active species and the catalyst has appropriate redox property,along with the larger amounts of surface Ce content and surface adsorbed oxygen species.Finally,a possible reaction mechanism via the Langmuir-Hinshelwood(L-H)mechanism is tentatively proposed to further understand the NH3-SCR reaction.
