The selective hydrogenation of polycyclic aromatic hydrocarbons(PAHs)from fluid catalytic cracking(FCC)slurry extract was conducted in a batch reactor over aγ-Al_(2)O_(3)-supported bimetallic Ni-W catalyst.For the Ni...The selective hydrogenation of polycyclic aromatic hydrocarbons(PAHs)from fluid catalytic cracking(FCC)slurry extract was conducted in a batch reactor over aγ-Al_(2)O_(3)-supported bimetallic Ni-W catalyst.For the Ni-W/γ-Al_(2)O_(3) catalyst,the experiment run was divided into three processes according to the reaction conditions used:(1)the absence of hydrogenation as both temperature and pressure increased;(2)the desulfurization of FCC slurry extract under a fixed pressure as the temperature increased;and(3)the selective hydrogenation of PAHs when both pressure and temperature remained constant.The hydrogen consumption could be accurately calculated from the Redlich–Kwong equation of state.The results for the removal of PAHs with hydrogenation displayed an excellent fit to the first-order kinetics.The apparent activation energy was determined to be 20.80 kJ/mol.展开更多
In this study,different loadings of x%Ni_(2)P/γ-Al_(2)O_(3)(x=6%,9%,12%,15%,18%)catalysts with aluminum oxide(Al_(2)O_(3))as the carrier,nickel chloride(NiCl2)as the nickel(Ni)source,and ammonium hypophosphite(NH_(4)...In this study,different loadings of x%Ni_(2)P/γ-Al_(2)O_(3)(x=6%,9%,12%,15%,18%)catalysts with aluminum oxide(Al_(2)O_(3))as the carrier,nickel chloride(NiCl2)as the nickel(Ni)source,and ammonium hypophosphite(NH_(4)H_(2)PO_(2))as the phosphorus(P)source were prepared by the equal volume impregnation method to investigate the effects of different loadings on the performance of the selective hydrogenation of diolefins and thiol etherification in LPG.The physicochemical properties of the catalysts were characterized by XRD,BET,SEM,TEM,H_(2)-TPR,and XPS,and the catalytic activity of the catalysts was evaluated in a fixed-bed microreactor.The results showed that a change in the loading affected the catalyst crystalline phase structure and size,specific surface area,P coverage,active phase dispersion,and catalytic activity.At 6%,9%,and 12%loadings the catalysts had an Ni phase but there was no obvious Ni_(2)P phase in the nickel phosphide;at 15%loading a single Ni_(2)P phase was obtained,and at 18%loading both Ni_(2)P and Ni1_(2)P_(5) phases appeared.There was a P enrichment on the catalyst surface,and the higher the loading the more P species were enriched on the surface,but some of the P was lost during the catalyst reduction process due to the production of phosphine(PH3)gas.The 15%Ni_(2)P/γ-Al_(2)O_(3) catalyst had the largest Ni/Al ratio and the best dispersion.The Ni_(2)P active phase size was small at about 4.25 nm and Ni_(2)P was uniformly dispersed on the catalyst surface without agglomeration.The 15%Ni_(2)P/γ-Al_(2)O_(3) catalyst had the best catalytic activity at a pressure of 2.0 MPa,a liquid hourly space velocity(LHSV)of 3.0 h-1,and a hydrogen to hydrocarbon ratio of 12.The 1,3-butadiene conversion was 97.45%and the methanethiol removal was 100%at a temperature of 140℃.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
Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promote...Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst.展开更多
Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO...Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO4.The Ce species in the catalysts prepared with different valences of the Ce precursors all exist as CeO2 on the Ru surface.The promoter CeO2alone could not improve the selectivity to cyclohexene of Ru catalysts.However,almost all the CeO2 in the catalysts could react with the reaction modifier ZnSO4 to form(Zn(OH)2)3(ZnSO4)(H2O)3 salt.The amount of the chemisorbed salt increased with the CeO2 loading,resulting in the decrease of the activity and the increase of the selectivity to cyclohexene of Ru catalyst.The Ru-Ce catalyst with the optimum Ce/Ru molar ratio of 0.19 gave a maximum cyclohexene yield of 57.4%.Moreover,this catalyst had good stability and excellent reusability.展开更多
A Ru-La/ZrO2 catalyst was prepared by the precipitation method, in which Ru was an active component, La was a promoter and ZrO2 was a dispersant. Comparing with the catalyst prepared by the chemical reduction method, ...A Ru-La/ZrO2 catalyst was prepared by the precipitation method, in which Ru was an active component, La was a promoter and ZrO2 was a dispersant. Comparing with the catalyst prepared by the chemical reduction method, the Ru-La/ZrO2 exhibited higher activity and better selectivity. At 140 ℃ and hydrogen pressure of 5 MPa, the C6H10 selectivity reached 70% at a C6H6 conversion of 35% for a reaction time was 5 min and the total La/Ru loading was 10%. Textural parameters of the catalyst were obtained by physical adsorption, BET surface area and specific pore volume measurements. The catalyst sample gave a BET area of 41 m2/g and a specific pore volume of 1.1 cm^3/g, and the most probable pore distribution was located at 5 to 10 nm. H2-TPR measurements showed that ruthenium oxide could be reduced to its metallic state at about 403 K. XRD determinations indicated that ruthenium and lanthanum were highly dispersed on the zirconia. A significant advantage of the Ru-La/ZrO2 catalyst is that it can be used directly in its unreduced state for the selective hydrogenation of benzene.展开更多
In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_...In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_(2) were synthesized via ultrasonic assisted impregnation-deposition method.Ultrafine Ru nanoparticles(<2 nm)were highly dispersed on nanosheet g-C_(3)N_(4)-H_(2).Strong interaction due to Ru-Nx coordination facilitated the uniform distribution of Ru species.Meanwhile,the involvement of surface basicity derived from abundant nitrogen sites was favourable for enhancing the selective hydrogenation performance of bi-benzene ring,i.e.,almost complete 4,40-diaminodiphenylmethane(MDA)conversion and>99%4,40-diaminodicyclohexylmethane selectivity,corresponding to a reaction activity of 35.7 mol_(MDA) mol_(Ru)^(-1) h^(-1).Moreover,the reaction activity of catalyst in the fifth run was 36.5 mol_(MDA) mol_(Ru)^(-1) h^(-1),which was comparable with that of the fresh one.The computational results showed that g-C_(3)N_(4) as support was favorable for adsorption and dissociation of H_(2) molecules.Moreover,the substrate scope can be successfully expanded to a variety of other aromatic diamines.Therefore,this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines.展开更多
In order to investigate the hydrofining process of LCO for producing aromatics and gasoline,the selective hydrogenation of polycyclic aromatic hydrocarbons(PAHs),a major component of light cycle oil(LCO),was studied u...In order to investigate the hydrofining process of LCO for producing aromatics and gasoline,the selective hydrogenation of polycyclic aromatic hydrocarbons(PAHs),a major component of light cycle oil(LCO),was studied using a NiMoW/Al_(2)O_(3)catalyst.Based on the study of the reversible hydrogenation reaction,PAHs in the selective hydrogenation process could be effectively simulated by the modeled CH and CH_(2) groups,and the hydrodesulfurization and hydrodenitrogenation kinetic models could be further established in this process.The results showed that the kinetic models developed could fit the experimental data effectively and predict the content of S,N,and aromatics in the selective hydrogenation products of LCO.展开更多
The highly dispersed Pt-ReOx (x _〈 1 ) sites ca. 0.5 nm in size were formed via a successive and strong inter- action of the Re precursor with titania and then of the Pt complex with deposited low-valent rhenium ox...The highly dispersed Pt-ReOx (x _〈 1 ) sites ca. 0.5 nm in size were formed via a successive and strong inter- action of the Re precursor with titania and then of the Pt complex with deposited low-valent rhenium oxide clusters. The size, charge and chemical composition were characterized by means of HRTEM/STEM with EDX mapping, XPS, and FTIRS. These sites with Re/Pt = 2 were shown to be highly active and selective in the hydrogenation of carboxylic acid to alcohol under very mild conditions (T = 130 ℃, P = 50 bar). The reaction rate constant for the hydrogenation of hexanoic acid increased linearly with the Pt content. As for the homogeneous pincer-type Ru-organic complexes, the active Pt-ReOx sites can dissociate heterolytically the molecular hydrogen with the formation of hydroxyl groups and Pt hydride for hydrogenation of the carboxylic group. Indeed, TOF of 20 h 1 and selectivity of 98%-99% are approaching the values typical of homogeneous catalysts. The first order kinetics described well the experimental data obtained in a wide range of reaction conditions.展开更多
Polymer-stabilized platinum/ruthenium bimetallic colloids (Pt/Ru) were synthesized by polyol reduction with microwave irradiation and characterized by TEM and XPS. The colloidal nanoparticles have small and narrow s...Polymer-stabilized platinum/ruthenium bimetallic colloids (Pt/Ru) were synthesized by polyol reduction with microwave irradiation and characterized by TEM and XPS. The colloidal nanoparticles have small and narrow size distributions. Catalytic performance of the Pt/Ru colloidal catalysts was investigated on the selective hydrogenation of crontonaldehyde (CRAL). A suitable amount of the added metal ions and base can improve the selectivity of CRAL to crotylalcohol (CROL) remarkably. The catalytic activity and the selectivity are dependent on the compositions of bimetallic colloids. Thereinto, PVP-stabilized 9Pt/1Ru colloid with a molar ratio of metals Pt:Ru = 9:1 shows the highest catalytic selectivity 77.3% to CROL at 333 K under 4.0 MPa of hydrogen.展开更多
Uniform Ni-B amorphous alloys about 14 nm have been prepared on CNTs-A support,named Ni-B/CNTs-A. In comparison with the Ni-B/CNTs amorphous catalyst, Ni-B/CNTs-A showed higher nickel loading, determined by ICP and be...Uniform Ni-B amorphous alloys about 14 nm have been prepared on CNTs-A support,named Ni-B/CNTs-A. In comparison with the Ni-B/CNTs amorphous catalyst, Ni-B/CNTs-A showed higher nickel loading, determined by ICP and better catalytic activity and ethylene selectivity in the acetylene hydrogenation reaction.展开更多
In the selective hydrogenation of diene (or alkyne) using heterogenized homogeneous catalyst, the high selectivity of monoene formation only appears in a very short time interval. The addition of suitable electron don...In the selective hydrogenation of diene (or alkyne) using heterogenized homogeneous catalyst, the high selectivity of monoene formation only appears in a very short time interval. The addition of suitable electron donors can decrease or even cease the monoene hydrogenation and thereby keep the high monoene selectivity after reaching its maximum.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
Supported Ru-based catalysts, prepared by a surfactant-stabilized colloidal method, exhibited a good selectivity to bis(4-aminocyclohexyl)methane via the hydrogenation of 4,4′-methylenedianiline. Transmission elect...Supported Ru-based catalysts, prepared by a surfactant-stabilized colloidal method, exhibited a good selectivity to bis(4-aminocyclohexyl)methane via the hydrogenation of 4,4′-methylenedianiline. Transmission electron microscopy(TEM) and X-ray diffraction(XRD) characterization showed Ru nanoparticles were well-dispersed on activated carbon, leading to the high activity and selectivity to the product.展开更多
The passivation of hydrogen atoms and the conformation of textured surfaces under oil-lubricated conditions are effective strategies to obtain amorphous carbon(a-C)films with extremely low friction.It is critical to u...The passivation of hydrogen atoms and the conformation of textured surfaces under oil-lubricated conditions are effective strategies to obtain amorphous carbon(a-C)films with extremely low friction.It is critical to understanding the influence mechanism of selective surface hydrogenation on the tribological behaviors of textured a-C film under oil-lubricated conditions.In particular,the interactions of hydrogen atoms and lubricants are confusing,which is enslaved to the in situ characterization technique.The reactive molecular dynamics(RMD)simulations were conducted to analyze the friction response of textured a-C films with selective hydrogenation surfaces under oil-lubricated conditions.The results indicate that the existence of hydrogen atoms on specific bump sites significantly decreases the friction coefficient(μ)of textured a-C film,which is highly dependent on the surface hydrogen content.The repulsion between hydrogen atoms and lubricant molecules prompts the formation of a dense lubricant film on the surface of the mating material.Interestingly,with the enhancement of the surface hydrogen content,the passivation of the friction interface and the repulsion between hydrogen atoms and lubricants play dominant roles in reducing the friction coefficient instead of hydrodynamic lubrication.展开更多
Selective hydrogenation of unsaturated aldehydes remains a grand challenge in controlling chemoselectivity up to now.We synthesized a series of PtFex/CeO_(2)catalysts,which were characterized by X-ray diffraction(XRD)...Selective hydrogenation of unsaturated aldehydes remains a grand challenge in controlling chemoselectivity up to now.We synthesized a series of PtFex/CeO_(2)catalysts,which were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)as well as temperature-programmed-reduction by hydrogen(H2-TPR).The catalytic performance of PtFex/CeO_(2),including cinnamaldehyde(CAL)conversion and selectivity toward cinnamyl alcohol(COL),is improved remarkably by introduction of Fe species in the Pt particles in the selective CAL hydrogenation under mild conditions.XPS results indicate that the electron transfer from Fe to Pt promotes CAL adsorption,resulting in the enhanced CAL conversion.And the COL selectivity is improved by CAL adsorption via an interaction of C=O group with surface oxygen defect sites because of interaction between PtFe and CeO_(2)support.In all,this study may provide some hints to design efficient nano Pt particles for the selective hydrogenation.展开更多
Hollow metal-organic frameworks(MOFs)have attracted increasing attention in the field of catalysis in recent years due to their unique cavity structure with fast mass-diffusion rates and easily accessible active sites...Hollow metal-organic frameworks(MOFs)have attracted increasing attention in the field of catalysis in recent years due to their unique cavity structure with fast mass-diffusion rates and easily accessible active sites.Here,we report the use of dynamic modulators,which are formed by the in-situ imine condensation reaction of 4-aminobenzoic acid and 4-formylbenzoic acid,to regulate the growth of MOFs to synthesize well-defined hollow thioether functionalized UiO-67(denoted as H-UiO-67-S)single crystals.After supporting Pd nanoparticles,the designed catalysts Pd@H-UiO-67-S show excellent conversion(>99.9%),selectivity(>99.9%),and stability(10 cycles)in the selective hydrogenation of nitrobenzenes with other reducible groups.Density functional theory calculations and the experimental results reveal that Pd nanoparticles not only selectively adsorb the nitro-groups on nitrobenzene,but also restrict the adsorption of the aniline product,due to the interaction of thioether with Pd in the confined pores of H-UiO-67-S,finally result in a significant increase in selectivity of nitro-hydrogenation.展开更多
Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto t...Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto the edges of two-dimensional(2D)1Tphase MoS_(2)(Pt1/1T-MOS_(2)SAC)as a proof-of-concept catalyst can efficiently convert biomass-derived MAH to SA with 100%conversion and 100%selectivity under mild conditions.The kinetic data and characterization results suggest that the catalytic performance of the edge-anchored Pt1/1T-MoS_(2)SAC originates from the facile H_(2)dissociation induced by the electron-deficient Pt1atoms and the pocket-like configuration of Pt1active site confines the adsorption configuration of MAH by the steric effect.The strategy of fabricating edge-confined catalysts offers a new direction to design novel SACs for biomass-derived transformations.展开更多
Catalytic selective hydrogenation of alkynes to the corresponding alkenes is an important process in industrial production.Modulating the selective hydrogenation of alkynes to the alkenes requires ingenuity since alke...Catalytic selective hydrogenation of alkynes to the corresponding alkenes is an important process in industrial production.Modulating the selective hydrogenation of alkynes to the alkenes requires ingenuity since alkenes can easily be converted into the corresponding alkanes under reductive conditions.Applying different reductive reagents to prevent the direct usage of H_(2)can avoid difficulties in hydrogen storage and transportation.Herein,we demonstrate a tandem process to hydrogenate phenylacetylene by CO and H_(2)Oviathecouplingof thelow-temperaturewater-gas shift reaction and selective hydrogenation of phenylacetylene utilizing theα-MoC catalyst.The reductive reagent,CO,not only produces H_(2)from H_(2)O to drive the reaction forward,but it also regulates the selectivity of styrene by preventing further hydrogenation.展开更多
Selective hydrogenation over earth-abundant metal catalysts is challenging but particularly valuable for practical applications in heterogeneous catalysis.Herein,we demonstrate that the catalytic selectivity of the co...Selective hydrogenation over earth-abundant metal catalysts is challenging but particularly valuable for practical applications in heterogeneous catalysis.Herein,we demonstrate that the catalytic selectivity of the commercial Raney nickel catalyst can be greatly tuned by modulation of the nickel surface by silica.Using quinoline hydrogenation as a model,we show that the silica-modified Raney nickel catalysts exhibit good activity,excellent selectivity,and long stability,whereas the undesired over-hydrogenation reactions are effectively hindered.In contrast,the pristine Raney nickel catalyst shows inferior selectivity for the targeted product.Mechanistic studies confirm a positive role of silica to facilitate the desorption of 1,2,3,4-tetrahydroquinoline from the catalyst surface,thus enhancing the product selectivity.展开更多
基金financially supported by the Natural Science Foundation of Jiangsu Province (Grant number:BK20140260)the Joint Project of Industry-UniversityResearch of Jiangsu Province (Grant number:BY2018158 and BY2021590)+1 种基金the CNPC-CZU Innovation Alliance,the Jiangsu Province Key Laboratory of Fine Petrochemical Engineering (Grant number:KF2302)the State Key Laboratory of Heavy Oil Processing。
文摘The selective hydrogenation of polycyclic aromatic hydrocarbons(PAHs)from fluid catalytic cracking(FCC)slurry extract was conducted in a batch reactor over aγ-Al_(2)O_(3)-supported bimetallic Ni-W catalyst.For the Ni-W/γ-Al_(2)O_(3) catalyst,the experiment run was divided into three processes according to the reaction conditions used:(1)the absence of hydrogenation as both temperature and pressure increased;(2)the desulfurization of FCC slurry extract under a fixed pressure as the temperature increased;and(3)the selective hydrogenation of PAHs when both pressure and temperature remained constant.The hydrogen consumption could be accurately calculated from the Redlich–Kwong equation of state.The results for the removal of PAHs with hydrogenation displayed an excellent fit to the first-order kinetics.The apparent activation energy was determined to be 20.80 kJ/mol.
文摘In this study,different loadings of x%Ni_(2)P/γ-Al_(2)O_(3)(x=6%,9%,12%,15%,18%)catalysts with aluminum oxide(Al_(2)O_(3))as the carrier,nickel chloride(NiCl2)as the nickel(Ni)source,and ammonium hypophosphite(NH_(4)H_(2)PO_(2))as the phosphorus(P)source were prepared by the equal volume impregnation method to investigate the effects of different loadings on the performance of the selective hydrogenation of diolefins and thiol etherification in LPG.The physicochemical properties of the catalysts were characterized by XRD,BET,SEM,TEM,H_(2)-TPR,and XPS,and the catalytic activity of the catalysts was evaluated in a fixed-bed microreactor.The results showed that a change in the loading affected the catalyst crystalline phase structure and size,specific surface area,P coverage,active phase dispersion,and catalytic activity.At 6%,9%,and 12%loadings the catalysts had an Ni phase but there was no obvious Ni_(2)P phase in the nickel phosphide;at 15%loading a single Ni_(2)P phase was obtained,and at 18%loading both Ni_(2)P and Ni1_(2)P_(5) phases appeared.There was a P enrichment on the catalyst surface,and the higher the loading the more P species were enriched on the surface,but some of the P was lost during the catalyst reduction process due to the production of phosphine(PH3)gas.The 15%Ni_(2)P/γ-Al_(2)O_(3) catalyst had the largest Ni/Al ratio and the best dispersion.The Ni_(2)P active phase size was small at about 4.25 nm and Ni_(2)P was uniformly dispersed on the catalyst surface without agglomeration.The 15%Ni_(2)P/γ-Al_(2)O_(3) catalyst had the best catalytic activity at a pressure of 2.0 MPa,a liquid hourly space velocity(LHSV)of 3.0 h-1,and a hydrogen to hydrocarbon ratio of 12.The 1,3-butadiene conversion was 97.45%and the methanethiol removal was 100%at a temperature of 140℃.
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Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst.
基金supported by the National Nature Science Foundation of China(21273205)the Innovation Found for Technology Based Firms of China(10C26214104505)+1 种基金the Chinese Post-doctorate Science Fund 51th batch of surface subsidizes(2012M511125)the Scientific Research Foundation of Graduate School of Zhengzhou University
文摘Ru-Ce catalysts were prepared by a co-precipitation method.The effects of Ce precursors with different valences and Ce contents on the catalytic performance of Ru-Ce catalysts were investigated in the presence of ZnSO4.The Ce species in the catalysts prepared with different valences of the Ce precursors all exist as CeO2 on the Ru surface.The promoter CeO2alone could not improve the selectivity to cyclohexene of Ru catalysts.However,almost all the CeO2 in the catalysts could react with the reaction modifier ZnSO4 to form(Zn(OH)2)3(ZnSO4)(H2O)3 salt.The amount of the chemisorbed salt increased with the CeO2 loading,resulting in the decrease of the activity and the increase of the selectivity to cyclohexene of Ru catalyst.The Ru-Ce catalyst with the optimum Ce/Ru molar ratio of 0.19 gave a maximum cyclohexene yield of 57.4%.Moreover,this catalyst had good stability and excellent reusability.
文摘A Ru-La/ZrO2 catalyst was prepared by the precipitation method, in which Ru was an active component, La was a promoter and ZrO2 was a dispersant. Comparing with the catalyst prepared by the chemical reduction method, the Ru-La/ZrO2 exhibited higher activity and better selectivity. At 140 ℃ and hydrogen pressure of 5 MPa, the C6H10 selectivity reached 70% at a C6H6 conversion of 35% for a reaction time was 5 min and the total La/Ru loading was 10%. Textural parameters of the catalyst were obtained by physical adsorption, BET surface area and specific pore volume measurements. The catalyst sample gave a BET area of 41 m2/g and a specific pore volume of 1.1 cm^3/g, and the most probable pore distribution was located at 5 to 10 nm. H2-TPR measurements showed that ruthenium oxide could be reduced to its metallic state at about 403 K. XRD determinations indicated that ruthenium and lanthanum were highly dispersed on the zirconia. A significant advantage of the Ru-La/ZrO2 catalyst is that it can be used directly in its unreduced state for the selective hydrogenation of benzene.
基金financially supported by the National Nature Science Foundation of China(21576272)“Transformational Technologies for Clean Energy and Demonstration”,Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA 21030600)Science and Technology Service Network Initiative,Chinese Academy of Sciences(KFJ-STS-QYZD-138).
文摘In this study,nanosheet g-C_(3)N_(4)-H_(2) was prepared by thermal exfoliation of bulk g-C_(3)N_(4) under hydrogen.A series of Ru/g-C_(3)N_(4)-H_(2) catalysts with Ru species supported on the nanosheet g-C_(3)N_(4)-H_(2) were synthesized via ultrasonic assisted impregnation-deposition method.Ultrafine Ru nanoparticles(<2 nm)were highly dispersed on nanosheet g-C_(3)N_(4)-H_(2).Strong interaction due to Ru-Nx coordination facilitated the uniform distribution of Ru species.Meanwhile,the involvement of surface basicity derived from abundant nitrogen sites was favourable for enhancing the selective hydrogenation performance of bi-benzene ring,i.e.,almost complete 4,40-diaminodiphenylmethane(MDA)conversion and>99%4,40-diaminodicyclohexylmethane selectivity,corresponding to a reaction activity of 35.7 mol_(MDA) mol_(Ru)^(-1) h^(-1).Moreover,the reaction activity of catalyst in the fifth run was 36.5 mol_(MDA) mol_(Ru)^(-1) h^(-1),which was comparable with that of the fresh one.The computational results showed that g-C_(3)N_(4) as support was favorable for adsorption and dissociation of H_(2) molecules.Moreover,the substrate scope can be successfully expanded to a variety of other aromatic diamines.Therefore,this work provides an efficient and green catalyst system for selective hydrogenation of aromatic diamines.
基金financially supported by the SINOPEC Research and Develepment Project (No.120051-1)
文摘In order to investigate the hydrofining process of LCO for producing aromatics and gasoline,the selective hydrogenation of polycyclic aromatic hydrocarbons(PAHs),a major component of light cycle oil(LCO),was studied using a NiMoW/Al_(2)O_(3)catalyst.Based on the study of the reversible hydrogenation reaction,PAHs in the selective hydrogenation process could be effectively simulated by the modeled CH and CH_(2) groups,and the hydrodesulfurization and hydrodenitrogenation kinetic models could be further established in this process.The results showed that the kinetic models developed could fit the experimental data effectively and predict the content of S,N,and aromatics in the selective hydrogenation products of LCO.
文摘The highly dispersed Pt-ReOx (x _〈 1 ) sites ca. 0.5 nm in size were formed via a successive and strong inter- action of the Re precursor with titania and then of the Pt complex with deposited low-valent rhenium oxide clusters. The size, charge and chemical composition were characterized by means of HRTEM/STEM with EDX mapping, XPS, and FTIRS. These sites with Re/Pt = 2 were shown to be highly active and selective in the hydrogenation of carboxylic acid to alcohol under very mild conditions (T = 130 ℃, P = 50 bar). The reaction rate constant for the hydrogenation of hexanoic acid increased linearly with the Pt content. As for the homogeneous pincer-type Ru-organic complexes, the active Pt-ReOx sites can dissociate heterolytically the molecular hydrogen with the formation of hydroxyl groups and Pt hydride for hydrogenation of the carboxylic group. Indeed, TOF of 20 h 1 and selectivity of 98%-99% are approaching the values typical of homogeneous catalysts. The first order kinetics described well the experimental data obtained in a wide range of reaction conditions.
基金This work was supported by the National Natural Science Foundation of China(Nos.29774037,29873058)the Chinese Academy of Sciences(No.KJ952-J1-508)is gratefully acknowledged.
文摘Polymer-stabilized platinum/ruthenium bimetallic colloids (Pt/Ru) were synthesized by polyol reduction with microwave irradiation and characterized by TEM and XPS. The colloidal nanoparticles have small and narrow size distributions. Catalytic performance of the Pt/Ru colloidal catalysts was investigated on the selective hydrogenation of crontonaldehyde (CRAL). A suitable amount of the added metal ions and base can improve the selectivity of CRAL to crotylalcohol (CROL) remarkably. The catalytic activity and the selectivity are dependent on the compositions of bimetallic colloids. Thereinto, PVP-stabilized 9Pt/1Ru colloid with a molar ratio of metals Pt:Ru = 9:1 shows the highest catalytic selectivity 77.3% to CROL at 333 K under 4.0 MPa of hydrogen.
基金The National Natural Science Foundation of China(No.20263003)supported this work.
文摘Uniform Ni-B amorphous alloys about 14 nm have been prepared on CNTs-A support,named Ni-B/CNTs-A. In comparison with the Ni-B/CNTs amorphous catalyst, Ni-B/CNTs-A showed higher nickel loading, determined by ICP and better catalytic activity and ethylene selectivity in the acetylene hydrogenation reaction.
文摘In the selective hydrogenation of diene (or alkyne) using heterogenized homogeneous catalyst, the high selectivity of monoene formation only appears in a very short time interval. The addition of suitable electron donors can decrease or even cease the monoene hydrogenation and thereby keep the high monoene selectivity after reaching its maximum.
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.
基金Supported by the National High Technology Research and Development Program of China(No.2007AA03Z345)
文摘Supported Ru-based catalysts, prepared by a surfactant-stabilized colloidal method, exhibited a good selectivity to bis(4-aminocyclohexyl)methane via the hydrogenation of 4,4′-methylenedianiline. Transmission electron microscopy(TEM) and X-ray diffraction(XRD) characterization showed Ru nanoparticles were well-dispersed on activated carbon, leading to the high activity and selectivity to the product.
基金financially supported by the National Natural Science Foundation of China(No.52175204)Basic Research Program of Xuzhou(No.KC21041)+2 种基金Material Science and Engineering Discipline Guidance Fund of China University of Mining and Technology(No.CUMTMS202211)Graduate Innovation Program of China University of Mining and Technology(No.2022WLJCRCZL281)Jiangsu Funding Program for Excellent Postdoctoral Talent(No.2022ZB522).
文摘The passivation of hydrogen atoms and the conformation of textured surfaces under oil-lubricated conditions are effective strategies to obtain amorphous carbon(a-C)films with extremely low friction.It is critical to understanding the influence mechanism of selective surface hydrogenation on the tribological behaviors of textured a-C film under oil-lubricated conditions.In particular,the interactions of hydrogen atoms and lubricants are confusing,which is enslaved to the in situ characterization technique.The reactive molecular dynamics(RMD)simulations were conducted to analyze the friction response of textured a-C films with selective hydrogenation surfaces under oil-lubricated conditions.The results indicate that the existence of hydrogen atoms on specific bump sites significantly decreases the friction coefficient(μ)of textured a-C film,which is highly dependent on the surface hydrogen content.The repulsion between hydrogen atoms and lubricant molecules prompts the formation of a dense lubricant film on the surface of the mating material.Interestingly,with the enhancement of the surface hydrogen content,the passivation of the friction interface and the repulsion between hydrogen atoms and lubricants play dominant roles in reducing the friction coefficient instead of hydrodynamic lubrication.
基金Project supported by the Natural Science Foundation of Inner Mongolia Autonomous Region(2020BS02016)the Program of Higher-level Talents of Inner Mongolia Agricultural University(NDYB2018-23)the Program of Scientific Research of Inner Mongolia Autonomous Region(NJZY19046)。
文摘Selective hydrogenation of unsaturated aldehydes remains a grand challenge in controlling chemoselectivity up to now.We synthesized a series of PtFex/CeO_(2)catalysts,which were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)as well as temperature-programmed-reduction by hydrogen(H2-TPR).The catalytic performance of PtFex/CeO_(2),including cinnamaldehyde(CAL)conversion and selectivity toward cinnamyl alcohol(COL),is improved remarkably by introduction of Fe species in the Pt particles in the selective CAL hydrogenation under mild conditions.XPS results indicate that the electron transfer from Fe to Pt promotes CAL adsorption,resulting in the enhanced CAL conversion.And the COL selectivity is improved by CAL adsorption via an interaction of C=O group with surface oxygen defect sites because of interaction between PtFe and CeO_(2)support.In all,this study may provide some hints to design efficient nano Pt particles for the selective hydrogenation.
基金The authors acknowledge financial support from the National Natural Science Foundation of China(Nos.21905195,M.T.Z.and 22103055,J.G.)Natural Science Foundation of Tianjin City(No.20JCYBJC00800,M.T.Z.)+1 种基金Science and Technology Plans of Tianjin(No.21ZYJDJC00050,J.G.)PEIYANG Young Scholars Program of Tianjin University(No.2020XRX-0023,M.T.Z.).
文摘Hollow metal-organic frameworks(MOFs)have attracted increasing attention in the field of catalysis in recent years due to their unique cavity structure with fast mass-diffusion rates and easily accessible active sites.Here,we report the use of dynamic modulators,which are formed by the in-situ imine condensation reaction of 4-aminobenzoic acid and 4-formylbenzoic acid,to regulate the growth of MOFs to synthesize well-defined hollow thioether functionalized UiO-67(denoted as H-UiO-67-S)single crystals.After supporting Pd nanoparticles,the designed catalysts Pd@H-UiO-67-S show excellent conversion(>99.9%),selectivity(>99.9%),and stability(10 cycles)in the selective hydrogenation of nitrobenzenes with other reducible groups.Density functional theory calculations and the experimental results reveal that Pd nanoparticles not only selectively adsorb the nitro-groups on nitrobenzene,but also restrict the adsorption of the aniline product,due to the interaction of thioether with Pd in the confined pores of H-UiO-67-S,finally result in a significant increase in selectivity of nitro-hydrogenation.
基金financially supported by the National Natural Science Foundation of China(Nos.21908079,21872145 and U21A20326)Jiangsu Specially-Appointed Professor Fund(No.1046010241211400)+4 种基金Natural Science Foundation of Jiangsu Province(Nos.BK20211239,BK20221541 and BK20201345)the State Key Laboratory of Fine ChemicalsDalian University of Technology(No.KF2005)Dalian Institute of Chemical Physics(No.DICP 1201943)the Central Laboratory,School of Chemical and Material Engineering,Jiangnan University。
文摘Selective hydrogenation of biomass-derived maleic anhydride(MAH)to succinic anhydride(SA)is valuable but remains a challenge due to the complicated reaction network.We here report that single Pt atoms decorated onto the edges of two-dimensional(2D)1Tphase MoS_(2)(Pt1/1T-MOS_(2)SAC)as a proof-of-concept catalyst can efficiently convert biomass-derived MAH to SA with 100%conversion and 100%selectivity under mild conditions.The kinetic data and characterization results suggest that the catalytic performance of the edge-anchored Pt1/1T-MoS_(2)SAC originates from the facile H_(2)dissociation induced by the electron-deficient Pt1atoms and the pocket-like configuration of Pt1active site confines the adsorption configuration of MAH by the steric effect.The strategy of fabricating edge-confined catalysts offers a new direction to design novel SACs for biomass-derived transformations.
基金the Natural Science Foundation of China(grant nos.21725301,21932002,and 21821004)the National Key R&D Program of China(grant no.2021YFA1501102)China Petrochemical Corporation(grant no.420043-10).
文摘Catalytic selective hydrogenation of alkynes to the corresponding alkenes is an important process in industrial production.Modulating the selective hydrogenation of alkynes to the alkenes requires ingenuity since alkenes can easily be converted into the corresponding alkanes under reductive conditions.Applying different reductive reagents to prevent the direct usage of H_(2)can avoid difficulties in hydrogen storage and transportation.Herein,we demonstrate a tandem process to hydrogenate phenylacetylene by CO and H_(2)Oviathecouplingof thelow-temperaturewater-gas shift reaction and selective hydrogenation of phenylacetylene utilizing theα-MoC catalyst.The reductive reagent,CO,not only produces H_(2)from H_(2)O to drive the reaction forward,but it also regulates the selectivity of styrene by preventing further hydrogenation.
基金the National Key Research and Development Program of China(2022YFA1503502)National Natural Science Foundation of China(U21B20101,21932006,and 22202175)China Postdoctoral Science Foundation(2021M700119).
文摘Selective hydrogenation over earth-abundant metal catalysts is challenging but particularly valuable for practical applications in heterogeneous catalysis.Herein,we demonstrate that the catalytic selectivity of the commercial Raney nickel catalyst can be greatly tuned by modulation of the nickel surface by silica.Using quinoline hydrogenation as a model,we show that the silica-modified Raney nickel catalysts exhibit good activity,excellent selectivity,and long stability,whereas the undesired over-hydrogenation reactions are effectively hindered.In contrast,the pristine Raney nickel catalyst shows inferior selectivity for the targeted product.Mechanistic studies confirm a positive role of silica to facilitate the desorption of 1,2,3,4-tetrahydroquinoline from the catalyst surface,thus enhancing the product selectivity.