Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging pro...Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic systems, study in the area is still limited. Herein, Ru-clusters/CeO2 is employed as a heterogeneous catalyst for the hydromethoxycarbonylation of styrene without any additives. After optimization of the reaction conditions, the conversion of styrene is > 99% with 83% and 12% regioselectivity of linear and branched ester, respectively. By using different supports(CeO2(nanoparticle), CeO2-rod, and CeO2-cube), three catalysts including Ru-clusters/CeO2, Ru/CeO2-rod, and Ru/CeO2-cube are prepared and applied in the reaction. Structural characterizations demonstrate that the L/B ratio is related to the Ru size of supported Ru catalysts. Further Raman characterization and NH3-TPD demonstrate that the metal-support interaction and the concentration of oxygen vacancy of the catalyst have a great influence on the Ru size. The mechanism and kinetic analysis for this reaction are also investigated in this work.展开更多
The catalytic activity measurement for the NO+CO reaction over CuO/CeO\-2/\%γ\%\|Al\-2O\-3 catalysts at a low\|temperature(200 ℃) shows that the activity is strongly related to ceria loading amount, and both surface...The catalytic activity measurement for the NO+CO reaction over CuO/CeO\-2/\%γ\%\|Al\-2O\-3 catalysts at a low\|temperature(200 ℃) shows that the activity is strongly related to ceria loading amount, and both surface dispersed ceria species and crystalline CeO\-2 shows a significant enhancement on the activity. The effect of ceria species is contributed to their promoting the reduction of copper oxide species.展开更多
The selective catalytic reduction(SCR) of NOx using MnOx and CeO2 supported on viscose-based active carbon fibers(ACF) at 120 ℃～270 ℃ relatively lower than the temperature when using V2O5/TiO2-anatase catalyst was ...The selective catalytic reduction(SCR) of NOx using MnOx and CeO2 supported on viscose-based active carbon fibers(ACF) at 120 ℃～270 ℃ relatively lower than the temperature when using V2O5/TiO2-anatase catalyst was studied.As a result,CeO2/ACF shows a better catalysis than MNOx/ACF,which is not affected by the reaction temperature. NO conversion of 85% is reached with the 10%-CeO2/ACF catalyst at the whole temperature window.Furthermore,a series of MnOx-CeO2/ACF composite catalysts were studied.The results show that the loading method of catalyst affects its activity.展开更多
Three kinds of REO modified CeO 2 ZrO 2 solid solutions were prepared by co precipitate method.TPR and XRD measurements have been used to characterize the effect of REO on the thermal stability and oxygen storage prop...Three kinds of REO modified CeO 2 ZrO 2 solid solutions were prepared by co precipitate method.TPR and XRD measurements have been used to characterize the effect of REO on the thermal stability and oxygen storage properties of CeO 2 ZrO 2 solid solutions,comparison being made with unmodified CeO 2 ZrO 2 solid solutions.The results indicated that the addition of REO to CeO 2 ZrO 2 solid solutions obviously improved the oxygen storage properties of the three kinds of solid solutions calcinated at 773K.Except for Zr rich solid solutions,the modified CeO 2 ZrO 2 solid soltuions calcinated at 1173K show higher thermal stability and oxygen storage properties than unmodified solid solutions.展开更多
文摘Hydroalkoxycarbonylation of olefins has been considered to be one of the most attractive methods to synthesize esters. Controlling the regioselectivities of linear esters(L) and branched esters(B) is a challenging project for researchers working in this reaction. Although most of the attention has been paid to control the regioselectivity through ligand design in homogeneous catalytic systems, study in the area is still limited. Herein, Ru-clusters/CeO2 is employed as a heterogeneous catalyst for the hydromethoxycarbonylation of styrene without any additives. After optimization of the reaction conditions, the conversion of styrene is > 99% with 83% and 12% regioselectivity of linear and branched ester, respectively. By using different supports(CeO2(nanoparticle), CeO2-rod, and CeO2-cube), three catalysts including Ru-clusters/CeO2, Ru/CeO2-rod, and Ru/CeO2-cube are prepared and applied in the reaction. Structural characterizations demonstrate that the L/B ratio is related to the Ru size of supported Ru catalysts. Further Raman characterization and NH3-TPD demonstrate that the metal-support interaction and the concentration of oxygen vacancy of the catalyst have a great influence on the Ru size. The mechanism and kinetic analysis for this reaction are also investigated in this work.
文摘The catalytic activity measurement for the NO+CO reaction over CuO/CeO\-2/\%γ\%\|Al\-2O\-3 catalysts at a low\|temperature(200 ℃) shows that the activity is strongly related to ceria loading amount, and both surface dispersed ceria species and crystalline CeO\-2 shows a significant enhancement on the activity. The effect of ceria species is contributed to their promoting the reduction of copper oxide species.
文摘The selective catalytic reduction(SCR) of NOx using MnOx and CeO2 supported on viscose-based active carbon fibers(ACF) at 120 ℃～270 ℃ relatively lower than the temperature when using V2O5/TiO2-anatase catalyst was studied.As a result,CeO2/ACF shows a better catalysis than MNOx/ACF,which is not affected by the reaction temperature. NO conversion of 85% is reached with the 10%-CeO2/ACF catalyst at the whole temperature window.Furthermore,a series of MnOx-CeO2/ACF composite catalysts were studied.The results show that the loading method of catalyst affects its activity.
文摘Three kinds of REO modified CeO 2 ZrO 2 solid solutions were prepared by co precipitate method.TPR and XRD measurements have been used to characterize the effect of REO on the thermal stability and oxygen storage properties of CeO 2 ZrO 2 solid solutions,comparison being made with unmodified CeO 2 ZrO 2 solid solutions.The results indicated that the addition of REO to CeO 2 ZrO 2 solid solutions obviously improved the oxygen storage properties of the three kinds of solid solutions calcinated at 773K.Except for Zr rich solid solutions,the modified CeO 2 ZrO 2 solid soltuions calcinated at 1173K show higher thermal stability and oxygen storage properties than unmodified solid solutions.
