Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increas...Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increasing coking problems, thereby raising concern to the refiner. This work investigated effect of nickel coexisting with vanadium in the FCC feedstock on the standard FCC catalyst during cracking process, in which destruction of active sites occurs as a result of the metals deposition. Laboratory simulated equilibrium catalysts (E-cats) were studied by XRD, FTIR spectroscopy, N-2 adsorption, solid state MAS-NMR, SEM and H-2-TPR. Results revealed that vanadium, above a certain concentration in the catalyst, under hydrothermal conditions, is highly detrimental to the catalyst's structure and activity. Conversely, nickel hardly affects the catalyst structure, but its co-presence in the catalyst reduces destructive effects of vanadium. The mechanism of nickel inhibition of vanadium poisoning of the catalyst is discussed. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Aluminated mesoporous silica was prepared by multiple post-grafting of alumina onto uniform mesoporous SiO2 ,which was assembled from monodisperse SiO2 microspheres.Hydrodesulfurization（HDS）catalyst was prepared by ...Aluminated mesoporous silica was prepared by multiple post-grafting of alumina onto uniform mesoporous SiO2 ,which was assembled from monodisperse SiO2 microspheres.Hydrodesulfurization（HDS）catalyst was prepared by loading Ni and Mo active components onto the aluminated uniform mesoporous SiO2 ,and its HDS catalytic performance was evaluated using hydrodesulfurization of dibenzothiophene as the probe reaction at 300℃ and 6.0 MPa in a tubular reactor.The samples were characterized by N2 physisorption,scanning electronic microscopy,Fourier transform infrared spectrum,X-ray diffraction（XRD）,temperature-programmed desorption of ammonia（NH3-TPD）,^27Al nuclear magnetic resonance（^27Al-NMR）and high-resolution transmission electron microscopy（HRTEM）.The results showed that the Si–OH group content of SiO2 was mainly dependent on the pretreatment conditions and had significant influence on the activity of the Ni Mo catalyst.The surface properties of the aluminated SiO2 varied with the Al2O3-grafting cycles.Generally after four cycles of grafting,the aluminated SiO2 behaved like amorphous alumina.In addition,plotting of activity of Ni Mo catalysts supported on aluminated meso–macroporous silica materials against the Al2O3-grafting cycle yields a volcano curve.展开更多
Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal lo...Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.展开更多
This article presents a detailed structural study of a new spherical Mg Cl2-supported Ti Cl4 Ziegler-Natta catalyst for isotactic propylene polymerization, and researches on the relationship between catalyst structure...This article presents a detailed structural study of a new spherical Mg Cl2-supported Ti Cl4 Ziegler-Natta catalyst for isotactic propylene polymerization, and researches on the relationship between catalyst structure and polymer properties. The spherical support with the chemical composition of CH3CH2 OMg OCH(CH2Cl)2 has been synthesized from a new dispersion system and is used as the supporting material to prepare Ziegler-Natta catalyst. The XRD analysis indicates that the catalyst is fully activated with δ-Mg Cl2 in the active catalyst. The far-IR spectrometric results confirm again the presence of δ-Mg Cl2 in the active catalyst. Textural property of the active catalyst exhibits high surface area coupled with high porosity. The high activity in propylene polymerization is mainly ascribed to the full activation and the porous structure of the catalyst. Scanning electron microscopy/energy dispersive spectrometer mapping results indicate a uniform titanium distribution throughout the catalyst particles. Particle size analysis shows that the catalyst has a narrow particle size distribution. The perfect spherical shape, uniform titanium distribution and narrow particle size distribution of the catalyst confirm the advantage of polymer particles production with less fines. The solid state 13 C NMR and mid-IR spectroscopic analyses indicate that there exists strong complexation between diisobutyl phthalate and Mg Cl2, which leads to the high isotacticity of polypropylene.展开更多
A method of synthesizing Ni-based catalysts supported on α-Al2O3-based foams was developed. The foams were impregnated with aqueous solutions of metal chlorides under an air atmosphere using an aerosol route. Separat...A method of synthesizing Ni-based catalysts supported on α-Al2O3-based foams was developed. The foams were impregnated with aqueous solutions of metal chlorides under an air atmosphere using an aerosol route. Separate procedures involved calcination to form oxides and drying to obtain chlorides on the foam surface. The synthesized samples were subsequently reduced with hydrogen. With respect to the Ni/Al2O3 catalysts, the chloride reduction route enabled the formation ofa Ni coating without agglomerates or cracks. Further research included catalyst modification by the addition of Pd, Cu, and Fe. The influences of the additives on the degree of reduction and on the low-temperature reduction effectiveness （533 and 633 K） were examined and compared for the catalysts obtained from oxides and chlorides. Greater degrees of reduction were achieved with chlorides, whereas Pd was the most effective modifier among those investigated. The reduction process was nearly complete at 533 K in the sample that contained 0.1wt% Pd. A lower reduction temperature was utilized, and the calcination step was avoided, which may enhance the economical and technological aspects of the developed catalyst production method.展开更多
VSb3W-Al2O3 catalysts for propane ammoxidation were prepared by the conventional slurry method and new slurry method,namely,the reduction-oxidation slurry method.The effect of preparation methods on the physicochemica...VSb3W-Al2O3 catalysts for propane ammoxidation were prepared by the conventional slurry method and new slurry method,namely,the reduction-oxidation slurry method.The effect of preparation methods on the physicochemical properties of VSb3W-Al2O3 catalysts were studied by N2 adsorption,XRD,XPS and Raman spectroscopy,and their catalytic performance for the ammoxidation of propane to acrylonitrile were tested.Compared with the VSb3W-Al2O3 catalyst prepared by the conventional slurry method,the VSb3W-Al2O3 catalyst prepared by the reduction-oxidation slurry method exhibited better propane conversion and acrylonitrile selectivity.This is due to that the reduction-oxidation treatment was advantageous for obtaining low valence state vanadium and high valence state antimony to form more rutile SbVO4,which is a vital active phase for propane ammoxidation.展开更多
PASCA, ESR and Microreactor, have been used to study the states and properties of coking deposits on catalyst. The results indicate that the C exists as three types of states on catalyst surface. The first and second ...PASCA, ESR and Microreactor, have been used to study the states and properties of coking deposits on catalyst. The results indicate that the C exists as three types of states on catalyst surface. The first and second types of carbon are the main reason of the catalyst deactivation, but the third type has a promoting role in n-C_7 hydrocracking reaction. The S_s-C interacts strongly with catalyst, forming metal-carbon-support interaction (MCSI).展开更多
The improper disposal of spent selective catalytic reduction (SCR) catalysts causes environmental pollution and metal resource waste.A novel process to recover anatase titanium dioxide (TiO_(2)) from spent SCR catalys...The improper disposal of spent selective catalytic reduction (SCR) catalysts causes environmental pollution and metal resource waste.A novel process to recover anatase titanium dioxide (TiO_(2)) from spent SCR catalysts was proposed.The process included alkali (NaOH) hydrothermal treatment,sulfuric acid washing,and calcination.Anatase TiO_(2) in spent SCR catalyst was reconstructed by forming Na_(2)Ti_(2)O_(4)(OH)_(2) nanosheet during NaOH hydrothermal treatment and H_(2)Ti_(2)O_(4)(OH)_(2) during sulfuric acid washing.Anatase TiO_(2) was recovered by decomposing H_(2)Ti_(2)O_(4)(OH)_(2) during calcination.The surface pore properties of the recovered anatase TiO_(2) were adequately improved,and its specific surface area (SSA) and pore volume (PV) were 85 m^(2)·g^(-1)and 0.40 cm^(3)·g^(-1),respectively.The elements affecting catalytic abilities(arsenic and sodium) were also removed.The SCR catalyst was resynthesized using the recovered TiO_(2) as raw material,and its catalytic performance in NO selective reduction was comparable with that of commercial SCR catalyst.This study realized the sustainable recycling of anatase TiO_(2) from spent SCR catalyst.展开更多
A novel molecular probe for identifying properties of supported transition metals and metal oxides catalysts was established.The catalytic mechanism of transition metals was proposed.
The microwave radiation method was introduced to prepare the Fe_2O_3/SO solid superacid.Its structure and properties were investigated by means of X-ray diffraction and infrared spectrum analyses as well as measuremen...The microwave radiation method was introduced to prepare the Fe_2O_3/SO solid superacid.Its structure and properties were investigated by means of X-ray diffraction and infrared spectrum analyses as well as measurement of magnetic susceptibility and rate of esterification. The structure of the superacids prepared in microwave field can be crystalline or non-crystalline, the latter has not been reported yet in literatures. Comparing with the traditional superacid, the non-crystalline Fe2O3/SO superacid prepared in microwave field has the highest magnetic susceptibility and catalytic activity. The di-coordination of Fe2O3 and SO and the S=O bi-bond were reinforced by microwave radiation, which is favorable for increasing the acid intensity of the Fe2O3/SO catalyst展开更多
The composite ZSM—5 zeolite/vermiculite catalyst,in which tiny ZSM—5 zeolite parti- cles embedded in the vermiculite substrate,has been synthesized by hydrothermal method with vermiculite as silicon source.The catal...The composite ZSM—5 zeolite/vermiculite catalyst,in which tiny ZSM—5 zeolite parti- cles embedded in the vermiculite substrate,has been synthesized by hydrothermal method with vermiculite as silicon source.The catalytic behavior of resulting catalyst for xylene isomerization,propylene aromatization and toluene disproportionation is better than that of HZSM—5 zeolite.展开更多
In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenoli...In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenolic resin were used as the main raw materials,and ferric nitrate as the catalyst to prepare refractories by nitriding at 1350℃.The effects of different catalyst supports(silicon powder,silicon powder+phenolic resin)on the formation of Si_(3)N_(4) in MgO-C refractories and the properties of refractories were studied.The results show that the silicon powder+resin catalyst support promotes the participation ofα-Si_(3)N_(4) in the reaction to generateβ-Si_(3)N_(4) and MgSiN_(2),and generates more SiC.However,this loading mode causes more gas to escape from the refractories and loosens the material structure,which reduces the mechanical properties.On the contrary,MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.展开更多
TiC-doped NaA1H4 complex hydrides were prepared by hydrogenation of ball-milled Nail/A1 mixture with x TiC powder （x = 0, 5%, 8%, 10%, mole fraction）. The effects of TiC catalyst content on the absorption/desorption...TiC-doped NaA1H4 complex hydrides were prepared by hydrogenation of ball-milled Nail/A1 mixture with x TiC powder （x = 0, 5%, 8%, 10%, mole fraction）. The effects of TiC catalyst content on the absorption/desorption behaviors of the samples were investigated. The results show that TiC can improve the hydriding/dehydriding kinetics of sodium aluminum hydride, the hydriding rate of the sample increases with increasing TiC content. It is found that the TiC-doped NaA1H4 composites have a relatively good cyclic stability. The composite doped with 10% TiC maintains steadily about 4.5% （mass fraction） hydrogen absorption capacity as against about 3.8% （mass fraction） hydrogen desorption capacity over 8 cycles. The particle sizes of the TiC-doped NaA1H4 composites can be reduced to 50-100 nm, which may play an important role in improving the hydriding/dehydriding kinetics.展开更多
基金financially supported by the Joint Funds of the National Natural Science Foundation of ChinaChina National Petroleum Corporation(U1362202)+4 种基金National Natural Science Foundation of China(21206195)the Fundamental Research Funds for the Central Universities(14CX02050A,14CX02123A)Shandong Provincial Natural Science Foundation(ZR2012BM014)the project sponsored by Scientific Research Foundation for Returned Overseas Chinese Scholarthe support from Chinese Government under the Chinese scholarship scheme for international students
文摘Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increasing coking problems, thereby raising concern to the refiner. This work investigated effect of nickel coexisting with vanadium in the FCC feedstock on the standard FCC catalyst during cracking process, in which destruction of active sites occurs as a result of the metals deposition. Laboratory simulated equilibrium catalysts (E-cats) were studied by XRD, FTIR spectroscopy, N-2 adsorption, solid state MAS-NMR, SEM and H-2-TPR. Results revealed that vanadium, above a certain concentration in the catalyst, under hydrothermal conditions, is highly detrimental to the catalyst's structure and activity. Conversely, nickel hardly affects the catalyst structure, but its co-presence in the catalyst reduces destructive effects of vanadium. The mechanism of nickel inhibition of vanadium poisoning of the catalyst is discussed. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
基金Financial support by the National Natural Science Foundation of China (Grant No. 91534120)the Shanghai Petrochemical Company of Sinopec (under the contract number 30450127-13-ZC0607-0001)
文摘Aluminated mesoporous silica was prepared by multiple post-grafting of alumina onto uniform mesoporous SiO2 ,which was assembled from monodisperse SiO2 microspheres.Hydrodesulfurization（HDS）catalyst was prepared by loading Ni and Mo active components onto the aluminated uniform mesoporous SiO2 ,and its HDS catalytic performance was evaluated using hydrodesulfurization of dibenzothiophene as the probe reaction at 300℃ and 6.0 MPa in a tubular reactor.The samples were characterized by N2 physisorption,scanning electronic microscopy,Fourier transform infrared spectrum,X-ray diffraction（XRD）,temperature-programmed desorption of ammonia（NH3-TPD）,^27Al nuclear magnetic resonance（^27Al-NMR）and high-resolution transmission electron microscopy（HRTEM）.The results showed that the Si–OH group content of SiO2 was mainly dependent on the pretreatment conditions and had significant influence on the activity of the Ni Mo catalyst.The surface properties of the aluminated SiO2 varied with the Al2O3-grafting cycles.Generally after four cycles of grafting,the aluminated SiO2 behaved like amorphous alumina.In addition,plotting of activity of Ni Mo catalysts supported on aluminated meso–macroporous silica materials against the Al2O3-grafting cycle yields a volcano curve.
基金Project supported by the National Natural Science Key Foundation of China (20333030)
文摘Ce0.67Zr0.33O2-Al2O3 solid solution was prepared by the co-precipitation method. Fe2O3-based catalysts supported on the solid solution were obtained by the impregnation method. The article revealed that the optimal loading amount of Fe2O3 on Ce0.67Zr0.33 O2-Al2O3 in our experimental condition for catalytic combustion of methane was 8% （ mass fraction）. The prepared catalysts were characterized by BET, TPR, XRD analyses, and their catalytic activity was investigated after being calcined at 873 K and after being aged in water gas at 1273 K. When the loading amount of Fe203 was 8% （ mass fraction）, the catalyst held the highest activity, and the best temperature speciality and thermal stability. The complete-conversion temperature of methane for fresh and aged sample was 788 and 838 K, respectively. The range between the light-off temperature and the complete-conversion temperature was only 15 K. The characterization results of XRD indicated that Fe2O3 was well dispersed on the Ce0.67Zr0.33O2-Al2O3 matrix. The results of BET and TPR were in good harmony with the catalytic activity results.
基金the Sinopec Beijing Research Institute of Chemical Industry for its financial support (No. 5-12ZS0419, 5-10ZS0245, 5-12ZS0270)
文摘This article presents a detailed structural study of a new spherical Mg Cl2-supported Ti Cl4 Ziegler-Natta catalyst for isotactic propylene polymerization, and researches on the relationship between catalyst structure and polymer properties. The spherical support with the chemical composition of CH3CH2 OMg OCH(CH2Cl)2 has been synthesized from a new dispersion system and is used as the supporting material to prepare Ziegler-Natta catalyst. The XRD analysis indicates that the catalyst is fully activated with δ-Mg Cl2 in the active catalyst. The far-IR spectrometric results confirm again the presence of δ-Mg Cl2 in the active catalyst. Textural property of the active catalyst exhibits high surface area coupled with high porosity. The high activity in propylene polymerization is mainly ascribed to the full activation and the porous structure of the catalyst. Scanning electron microscopy/energy dispersive spectrometer mapping results indicate a uniform titanium distribution throughout the catalyst particles. Particle size analysis shows that the catalyst has a narrow particle size distribution. The perfect spherical shape, uniform titanium distribution and narrow particle size distribution of the catalyst confirm the advantage of polymer particles production with less fines. The solid state 13 C NMR and mid-IR spectroscopic analyses indicate that there exists strong complexation between diisobutyl phthalate and Mg Cl2, which leads to the high isotacticity of polypropylene.
基金financially supported by the Ministry of Education, Science and Technological Development of the Republic of Serbia and is a result of projects No. 34033 and No. 34023
文摘A method of synthesizing Ni-based catalysts supported on α-Al2O3-based foams was developed. The foams were impregnated with aqueous solutions of metal chlorides under an air atmosphere using an aerosol route. Separate procedures involved calcination to form oxides and drying to obtain chlorides on the foam surface. The synthesized samples were subsequently reduced with hydrogen. With respect to the Ni/Al2O3 catalysts, the chloride reduction route enabled the formation ofa Ni coating without agglomerates or cracks. Further research included catalyst modification by the addition of Pd, Cu, and Fe. The influences of the additives on the degree of reduction and on the low-temperature reduction effectiveness （533 and 633 K） were examined and compared for the catalysts obtained from oxides and chlorides. Greater degrees of reduction were achieved with chlorides, whereas Pd was the most effective modifier among those investigated. The reduction process was nearly complete at 533 K in the sample that contained 0.1wt% Pd. A lower reduction temperature was utilized, and the calcination step was avoided, which may enhance the economical and technological aspects of the developed catalyst production method.
基金support from the National Basic Research Program of China (No.2010CB732300)China Petroleum & Chemical Corporation (No.204061)
文摘VSb3W-Al2O3 catalysts for propane ammoxidation were prepared by the conventional slurry method and new slurry method,namely,the reduction-oxidation slurry method.The effect of preparation methods on the physicochemical properties of VSb3W-Al2O3 catalysts were studied by N2 adsorption,XRD,XPS and Raman spectroscopy,and their catalytic performance for the ammoxidation of propane to acrylonitrile were tested.Compared with the VSb3W-Al2O3 catalyst prepared by the conventional slurry method,the VSb3W-Al2O3 catalyst prepared by the reduction-oxidation slurry method exhibited better propane conversion and acrylonitrile selectivity.This is due to that the reduction-oxidation treatment was advantageous for obtaining low valence state vanadium and high valence state antimony to form more rutile SbVO4,which is a vital active phase for propane ammoxidation.
文摘PASCA, ESR and Microreactor, have been used to study the states and properties of coking deposits on catalyst. The results indicate that the C exists as three types of states on catalyst surface. The first and second types of carbon are the main reason of the catalyst deactivation, but the third type has a promoting role in n-C_7 hydrocracking reaction. The S_s-C interacts strongly with catalyst, forming metal-carbon-support interaction (MCSI).
基金supported by the National Natural Science Foundation of China (52274411)the National Natural Science Foundation of China (51904287)the Innovation Academy for Green Manufacture,Chinese Academy of Sciences (IAGM2022D11)。
文摘The improper disposal of spent selective catalytic reduction (SCR) catalysts causes environmental pollution and metal resource waste.A novel process to recover anatase titanium dioxide (TiO_(2)) from spent SCR catalysts was proposed.The process included alkali (NaOH) hydrothermal treatment,sulfuric acid washing,and calcination.Anatase TiO_(2) in spent SCR catalyst was reconstructed by forming Na_(2)Ti_(2)O_(4)(OH)_(2) nanosheet during NaOH hydrothermal treatment and H_(2)Ti_(2)O_(4)(OH)_(2) during sulfuric acid washing.Anatase TiO_(2) was recovered by decomposing H_(2)Ti_(2)O_(4)(OH)_(2) during calcination.The surface pore properties of the recovered anatase TiO_(2) were adequately improved,and its specific surface area (SSA) and pore volume (PV) were 85 m^(2)·g^(-1)and 0.40 cm^(3)·g^(-1),respectively.The elements affecting catalytic abilities(arsenic and sodium) were also removed.The SCR catalyst was resynthesized using the recovered TiO_(2) as raw material,and its catalytic performance in NO selective reduction was comparable with that of commercial SCR catalyst.This study realized the sustainable recycling of anatase TiO_(2) from spent SCR catalyst.
文摘A novel molecular probe for identifying properties of supported transition metals and metal oxides catalysts was established.The catalytic mechanism of transition metals was proposed.
文摘The microwave radiation method was introduced to prepare the Fe_2O_3/SO solid superacid.Its structure and properties were investigated by means of X-ray diffraction and infrared spectrum analyses as well as measurement of magnetic susceptibility and rate of esterification. The structure of the superacids prepared in microwave field can be crystalline or non-crystalline, the latter has not been reported yet in literatures. Comparing with the traditional superacid, the non-crystalline Fe2O3/SO superacid prepared in microwave field has the highest magnetic susceptibility and catalytic activity. The di-coordination of Fe2O3 and SO and the S=O bi-bond were reinforced by microwave radiation, which is favorable for increasing the acid intensity of the Fe2O3/SO catalyst
文摘The composite ZSM—5 zeolite/vermiculite catalyst,in which tiny ZSM—5 zeolite parti- cles embedded in the vermiculite substrate,has been synthesized by hydrothermal method with vermiculite as silicon source.The catalytic behavior of resulting catalyst for xylene isomerization,propylene aromatization and toluene disproportionation is better than that of HZSM—5 zeolite.
基金supported by the National Natural Science Foundation of China(U20A20239)the Natural Science Foundation of Hubei Province(2020CFB692)the Scientific Research Fund of Hunan Provincial Education Department(18A428).
文摘In order to investigate the effect of the catalyst loading mode on the mechanical properties of Si_(3)N_(4) composite MgO-C refractories prepared by nitridation,fused magnesia,flake graphite,silicon powder,and phenolic resin were used as the main raw materials,and ferric nitrate as the catalyst to prepare refractories by nitriding at 1350℃.The effects of different catalyst supports(silicon powder,silicon powder+phenolic resin)on the formation of Si_(3)N_(4) in MgO-C refractories and the properties of refractories were studied.The results show that the silicon powder+resin catalyst support promotes the participation ofα-Si_(3)N_(4) in the reaction to generateβ-Si_(3)N_(4) and MgSiN_(2),and generates more SiC.However,this loading mode causes more gas to escape from the refractories and loosens the material structure,which reduces the mechanical properties.On the contrary,MgO-C refractories prepared by nitridation with silicon powder-supported catalysts under the same conditions show higher density and better mechanical properties.
基金Project(2010CB631300)supported by the National Basic Research Program of ChinaProjects(50871099,51001090)supported by the National Natural Science Foundation of China+1 种基金Projects(20080440196,200902622)supported by the China Postdoctoral Science FoundationProject(20090101110050)supported by the University Doctoral Foundation of the Ministry of Education,China
文摘TiC-doped NaA1H4 complex hydrides were prepared by hydrogenation of ball-milled Nail/A1 mixture with x TiC powder （x = 0, 5%, 8%, 10%, mole fraction）. The effects of TiC catalyst content on the absorption/desorption behaviors of the samples were investigated. The results show that TiC can improve the hydriding/dehydriding kinetics of sodium aluminum hydride, the hydriding rate of the sample increases with increasing TiC content. It is found that the TiC-doped NaA1H4 composites have a relatively good cyclic stability. The composite doped with 10% TiC maintains steadily about 4.5% （mass fraction） hydrogen absorption capacity as against about 3.8% （mass fraction） hydrogen desorption capacity over 8 cycles. The particle sizes of the TiC-doped NaA1H4 composites can be reduced to 50-100 nm, which may play an important role in improving the hydriding/dehydriding kinetics.
