Highly active and stable nickel catalyst for dehydrogenation of methane and hydrogenation of benzene is prepared from a precursor with hydrotalcite-like anionic clam structure by coprecipitation. The nickel particles ...Highly active and stable nickel catalyst for dehydrogenation of methane and hydrogenation of benzene is prepared from a precursor with hydrotalcite-like anionic clam structure by coprecipitation. The nickel particles have a narrow size distribution in several nanometers, and have a strong interaction with other components such as Al2O3. This catalyst is highly sensitive to further modification by doping and to reaction condition. On a modified catalyst, benzene hydrogenation to cyclohexane proceeds to complete at 373 K. While on another catalyst, different structured nanocarbons are obtained at moderate temperatures. It is found that the thioresistance of the nickel catalyst in hydrogenation can be improved by doping.展开更多
Colloidal dispersion of nano-Ru/SiO2 in PEG （polyethylene glycol, M.W.=400） was used for benzene hydrogenation. The system has the features of easy catalyst＇s recycling and high catalyst stability.
A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize ...A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.展开更多
The effect of La on the performance of a supported RuB amorphous alloy catalyst for benzene selective hydrogenation was studied by means of activity and selectivity tests, such as HRTEM, SAED, XPS, and XRD. The result...The effect of La on the performance of a supported RuB amorphous alloy catalyst for benzene selective hydrogenation was studied by means of activity and selectivity tests, such as HRTEM, SAED, XPS, and XRD. The results show that the addition of La to RuB amorphous alloy catalyst can evidently increase the activity and improve the thermal stability of RuB amorphous alloy to refrain its crystallization. The promoting effect of La on the activity of RuB amorphous alloy catalyst is because of the high dispersion of the active components.展开更多
The effect of support calcination temperature on the benzene selective hydrogenation performance of the Ru-Ce-B/ZrO2 catalysts was investigated.It was found that with increasing calcination temperature,the surface are...The effect of support calcination temperature on the benzene selective hydrogenation performance of the Ru-Ce-B/ZrO2 catalysts was investigated.It was found that with increasing calcination temperature,the surface area decreased,on the contrary,the pore size and the amount of monoclinic phase increased.With increasing support calcination temperature,the activity of the catalyst roughly decreased and cyclohexene selectivity increased.The activity decreased due to the decrease of the surface areas.The increase of the cyclohexene selectivity was correlated not only with the decrease of the surface areas but also with the increase of monoclinic phases,rich in surface hydroxyl,and the enlarged pore size of zirconia.This suggests the monoclinic zirconia with a medium surface area,rather than a big one,and a mesoporous structure,even including some macropores,is an ideal support of the catalyst for benzene selective hydrogenation.展开更多
Gas phase hydrogenation of benzene was selected as probe reaction to study the effects of heavy rare earth elements on the catalytic activity and sulfur resistance of amorphous NiB alloy. XRD, DSC, CO chemical adsorp...Gas phase hydrogenation of benzene was selected as probe reaction to study the effects of heavy rare earth elements on the catalytic activity and sulfur resistance of amorphous NiB alloy. XRD, DSC, CO chemical adsorption, TP5 and TPD were used to characterize the bulk and the surface properties of the alloys, respectively. The results indicate that the addition of a small amount of heavy rare earth (HRE) elements obviously improves the activity, thermal stability and sulfur resistance of amorphous NiB alloy. The HRE can alter H 2 adsorption bond strength, increase the surface area of active nickel and the number of active centers over the surface of NiB alloy and it also can decrease the activation energy of NiB alloy for benzene hydrogenation. There are four kinds of adsorbing sites over the surface of NiB and NiBRE, only three kinds of them have concerned with the reaction.展开更多
Amorphous NiB andNiBRE alloys were prepared bychemical reduction method. Theeffects of Eu, Gd, Tb on thecatalytic activity and suifur resistance of amorphous NiB alloywere studied for the first time inthe paper. XRD w...Amorphous NiB andNiBRE alloys were prepared bychemical reduction method. Theeffects of Eu, Gd, Tb on thecatalytic activity and suifur resistance of amorphous NiB alloywere studied for the first time inthe paper. XRD was used to examine the structure. The surfaceproperties of the alloys were charaeterized by TPR and TPD. Results indicate that the addition ofa small amount of rare earth elements improves the activity andsulfur resistance of amorphousNiB alloy because of the interaction between RE and NiB alloy.It makes oxidized nickel and NiB-O species reduce more easilyand difficultly, respectively,whieh increases the number of active sites. It also changes thestrength of absorbing bond and decreases the activation energy forbenzene hydrogenation over NiB alloy. The results also indicate thatthe active sites of NiB alloy are related to the reduced nickel and NiB-O species.展开更多
基金Supported by the National Natural Science Foundation of China(No. 29792070-9, 29876032).
文摘Highly active and stable nickel catalyst for dehydrogenation of methane and hydrogenation of benzene is prepared from a precursor with hydrotalcite-like anionic clam structure by coprecipitation. The nickel particles have a narrow size distribution in several nanometers, and have a strong interaction with other components such as Al2O3. This catalyst is highly sensitive to further modification by doping and to reaction condition. On a modified catalyst, benzene hydrogenation to cyclohexane proceeds to complete at 373 K. While on another catalyst, different structured nanocarbons are obtained at moderate temperatures. It is found that the thioresistance of the nickel catalyst in hydrogenation can be improved by doping.
基金Thanks the financial support from the National Natural Science Foundation of China （No. 20376013）Fok Ying Tung Education Foundation （No. 91071） Specialized Research Fund for the Doctoral Program Foundation of Higher Education （No. 20020141004）.
文摘Colloidal dispersion of nano-Ru/SiO2 in PEG （polyethylene glycol, M.W.=400） was used for benzene hydrogenation. The system has the features of easy catalyst＇s recycling and high catalyst stability.
文摘A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.
文摘The effect of La on the performance of a supported RuB amorphous alloy catalyst for benzene selective hydrogenation was studied by means of activity and selectivity tests, such as HRTEM, SAED, XPS, and XRD. The results show that the addition of La to RuB amorphous alloy catalyst can evidently increase the activity and improve the thermal stability of RuB amorphous alloy to refrain its crystallization. The promoting effect of La on the activity of RuB amorphous alloy catalyst is because of the high dispersion of the active components.
文摘The effect of support calcination temperature on the benzene selective hydrogenation performance of the Ru-Ce-B/ZrO2 catalysts was investigated.It was found that with increasing calcination temperature,the surface area decreased,on the contrary,the pore size and the amount of monoclinic phase increased.With increasing support calcination temperature,the activity of the catalyst roughly decreased and cyclohexene selectivity increased.The activity decreased due to the decrease of the surface areas.The increase of the cyclohexene selectivity was correlated not only with the decrease of the surface areas but also with the increase of monoclinic phases,rich in surface hydroxyl,and the enlarged pore size of zirconia.This suggests the monoclinic zirconia with a medium surface area,rather than a big one,and a mesoporous structure,even including some macropores,is an ideal support of the catalyst for benzene selective hydrogenation.
文摘Gas phase hydrogenation of benzene was selected as probe reaction to study the effects of heavy rare earth elements on the catalytic activity and sulfur resistance of amorphous NiB alloy. XRD, DSC, CO chemical adsorption, TP5 and TPD were used to characterize the bulk and the surface properties of the alloys, respectively. The results indicate that the addition of a small amount of heavy rare earth (HRE) elements obviously improves the activity, thermal stability and sulfur resistance of amorphous NiB alloy. The HRE can alter H 2 adsorption bond strength, increase the surface area of active nickel and the number of active centers over the surface of NiB alloy and it also can decrease the activation energy of NiB alloy for benzene hydrogenation. There are four kinds of adsorbing sites over the surface of NiB and NiBRE, only three kinds of them have concerned with the reaction.
文摘Amorphous NiB andNiBRE alloys were prepared bychemical reduction method. Theeffects of Eu, Gd, Tb on thecatalytic activity and suifur resistance of amorphous NiB alloywere studied for the first time inthe paper. XRD was used to examine the structure. The surfaceproperties of the alloys were charaeterized by TPR and TPD. Results indicate that the addition ofa small amount of rare earth elements improves the activity andsulfur resistance of amorphousNiB alloy because of the interaction between RE and NiB alloy.It makes oxidized nickel and NiB-O species reduce more easilyand difficultly, respectively,whieh increases the number of active sites. It also changes thestrength of absorbing bond and decreases the activation energy forbenzene hydrogenation over NiB alloy. The results also indicate thatthe active sites of NiB alloy are related to the reduced nickel and NiB-O species.
