CuO/CeO_2 catalysts were prepared by a coprecipitation method and tested for CO removal from reformed fuels via selective oxidation. The influence of the calcination temperature on the chemical compositions and cataly...CuO/CeO_2 catalysts were prepared by a coprecipitation method and tested for CO removal from reformed fuels via selective oxidation. The influence of the calcination temperature on the chemical compositions and catalytic performance of CuO/CeO_2 catalysts were studied. It was found that CuO/CeO_2 catalysts exhibit excellent CO oxidation activity and selectivity,and the complete removal of CO is attained when the catalysts are calcined at appropriate temperatures. XRD, TPR and XPS results indicate that CuO/CeO_2 catalysts exhibit higher catalytic performance in CO selective oxidation due to the strong interaction between copper oxide and cerium dioxide, which promotes the dispersion and hydrogen reduction activity of copper.展开更多
The catalytic oxidation of ethyl acetate(EA)was studied over CuO/CeO_(2) catalysts which were prepared by ball milling with different precursors(copper oxide,cerium acetate,cerium dioxide,copper acetate and cerium hyd...The catalytic oxidation of ethyl acetate(EA)was studied over CuO/CeO_(2) catalysts which were prepared by ball milling with different precursors(copper oxide,cerium acetate,cerium dioxide,copper acetate and cerium hydroxide).The CuO/CeO_(2) catalyst(O-A)prepared with copper oxide and cerium acetate as precursors shows very high catalytic activity that 100%EA conversion is achieved at low temperature of 220℃.It is found that specific surface area(112.8 m^(2)/g),particle size of CuO(3.5 nm)and proportion of oxygen vacancies are prominent on the O-A catalyst.Oxygen vacancies in CeO_(2)support are beneficial to enhancing the adsorption and activation of the oxygen.More finely dispersed CuO particles and oxygen vacancies which are derived from the synergistic interaction of Cu-Ce species play an important role in the catalytic oxidation of EA.展开更多
The performances of CO selective oxidation in hydrogen-rich gas over fourcatalytic systems of CuO/ZrO_2, CuO/MnO_2, CuO/CoO and CuO/CeO_2 were compared. The reducibility ofthese catalysts and the effect of CuO and CeO...The performances of CO selective oxidation in hydrogen-rich gas over fourcatalytic systems of CuO/ZrO_2, CuO/MnO_2, CuO/CoO and CuO/CeO_2 were compared. The reducibility ofthese catalysts and the effect of CuO and CeO_2 molar ratio of CuO/CeO_2 catalysts on the activityof selective CO oxidation are investigated by XRD and TPR methods. The results show that thecatalysts with the exception of CuO/ZrO_2 have the interactions between CuO and CoO, CeO_2 or MnO_2,which result in a decrease in the reduction temperature. Among the catalysts studied, CuO/ZrO_2catalyst shows the lowest catalytic activity while CuO/CeO_2 catalyst exhibits the best catalyticperformance. The CuO(10%)/CeO_2 catalyst attains the highest CO conversion and selectivity at 140and 160℃. The addition of 9% H_2O in the reactant feed decreases the activity of CuO/CeO_2 catalystbut increases its CO selectivity.展开更多
Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low t...Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H_2 temperature-programmed reduction（TPR） and NH_3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu^（2＋） species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO_2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH_3 by O_2 and decreased surface acidity of the catalyst.展开更多
文摘CuO/CeO_2 catalysts were prepared by a coprecipitation method and tested for CO removal from reformed fuels via selective oxidation. The influence of the calcination temperature on the chemical compositions and catalytic performance of CuO/CeO_2 catalysts were studied. It was found that CuO/CeO_2 catalysts exhibit excellent CO oxidation activity and selectivity,and the complete removal of CO is attained when the catalysts are calcined at appropriate temperatures. XRD, TPR and XPS results indicate that CuO/CeO_2 catalysts exhibit higher catalytic performance in CO selective oxidation due to the strong interaction between copper oxide and cerium dioxide, which promotes the dispersion and hydrogen reduction activity of copper.
基金Project supported by the Shanghai Rising-Star Program(21QA1406600)the NSFC-Zhejiang Joint Fund for Integration of Industrialization and Diversification(U1809214)Zhoushan City Science&Technology Research Project(2019C21012).
文摘The catalytic oxidation of ethyl acetate(EA)was studied over CuO/CeO_(2) catalysts which were prepared by ball milling with different precursors(copper oxide,cerium acetate,cerium dioxide,copper acetate and cerium hydroxide).The CuO/CeO_(2) catalyst(O-A)prepared with copper oxide and cerium acetate as precursors shows very high catalytic activity that 100%EA conversion is achieved at low temperature of 220℃.It is found that specific surface area(112.8 m^(2)/g),particle size of CuO(3.5 nm)and proportion of oxygen vacancies are prominent on the O-A catalyst.Oxygen vacancies in CeO_(2)support are beneficial to enhancing the adsorption and activation of the oxygen.More finely dispersed CuO particles and oxygen vacancies which are derived from the synergistic interaction of Cu-Ce species play an important role in the catalytic oxidation of EA.
基金This work was financially supported by Guangdong Province Natural Science Foundation of China(000435), the Doctoral Program Foundation of the Ministry of Education (20010561003) Guangzhou Municipal Science and Technology Project(2001J1C0211)
文摘The performances of CO selective oxidation in hydrogen-rich gas over fourcatalytic systems of CuO/ZrO_2, CuO/MnO_2, CuO/CoO and CuO/CeO_2 were compared. The reducibility ofthese catalysts and the effect of CuO and CeO_2 molar ratio of CuO/CeO_2 catalysts on the activityof selective CO oxidation are investigated by XRD and TPR methods. The results show that thecatalysts with the exception of CuO/ZrO_2 have the interactions between CuO and CoO, CeO_2 or MnO_2,which result in a decrease in the reduction temperature. Among the catalysts studied, CuO/ZrO_2catalyst shows the lowest catalytic activity while CuO/CeO_2 catalyst exhibits the best catalyticperformance. The CuO(10%)/CeO_2 catalyst attains the highest CO conversion and selectivity at 140and 160℃. The addition of 9% H_2O in the reactant feed decreases the activity of CuO/CeO_2 catalystbut increases its CO selectivity.
基金Project supported by the the National Natural Science Foundation of China(51372137)Ministry of Science and Technology,China(2015AA034603)
文摘Cu/ZSM-5 and CeO_2-modified Cu/ZSM-5 catalysts were prepared by a wetness impregnation method. The addition of CeO_2 was found to enhance the NO_x selective catalytic reduction（SCR） activity of the catalyst at low temperatures, but the high-temperature activity was weakened. The catalysts were characterized by X-ray diffraction（XRD）, nitrogen physisorption, inductively coupled plasma optical emission spectrometry（ICP-OES）, X-ray photoelectron spectroscopy（XPS）, electron paramagnetic resonance（EPR）, H_2 temperature-programmed reduction（TPR） and NH_3 temperature-programmed desorption（TPD）. The results showed that more CuO clusters instead of isolated Cu^（2＋） species were obtained on the modified catalyst. These active CuO clusters, as well as the Cu-Ce synergistic effect, improved the redox property of the catalyst and low-temperatures SCR activity via promoting the oxidation of NO to NO_2 and fast SCR reaction. The loss in high-temperatures activity was attributed to the enhanced competitive oxidation of NH_3 by O_2 and decreased surface acidity of the catalyst.
