A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods....A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods. Evaluation of catalytic activity of both the commercial Y-zeolite and the novel Y-zeolite-containing composite material was carried out in the pulse micro-chromatography platform with two probe molecules of different molecular sizes： VGO feedstock and 1,3,5 tri-isopropyl benzene. It was found that the Y-zeolite-containing composite material was richer in external surface and meso-/macro-pores; the Y-zeolite-containing composite material demonstrated a smaller rate of deactivation compared to the commercial Y-zeolite.展开更多
The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction（...The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction（XRD）,N2 adsorption-desorption studies,transmission electron microscopy（TEM）and surface morphology analysis（SEM）,surface acid（NH3-TPD）,reducibility properties（TPR）,X-ray energy dispersive spectrometer（EDS）and thermogravimetric analysis（TG/DTG）.A l/La composite mesoporous material were synthesized with n（Al）︰n（La）=70︰1.0,80°C of reaction temperature,20 h of reaction time,12 h of crystallization time,650°C of calcination temperature.The specific surface area of the sample is 273.90 m 2 ·g ？1 ,with the average diameter 5.642 nm and pore volume 0.2354 cm 3 ·g ？1 .The samples have mesoporous structure and its particles are similar to a worm-shaped tubular structure.The influence of calcination temperature on the surface physical and chemical properties of Al/La composited mesoporous materials was examined,and the results showed that the acid strength was increased but the amount of acidic sites is decreased as the calcination temperature increased.It was found that the sample calcined at 650°C had appropriate acid content,acid strength and better reducibility.展开更多
A mesoporous LiFe0.99Mo0.01PO4/C composite was synthesized by the sol-gel method using （NH4）2MoO4 as a doping starting material. The formation of conductive carbon, metal doping and mesopores was achieved simultaneo...A mesoporous LiFe0.99Mo0.01PO4/C composite was synthesized by the sol-gel method using （NH4）2MoO4 as a doping starting material. The formation of conductive carbon, metal doping and mesopores was achieved simultaneously in the prepared material. The characterizations of crystal structures and microstructures were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, extended X-ray-absorption fine-structure （EXAFS） and X-ray-absorption near-structure spectroscopy （XANES） while the surface area was determined using N2 adsorption techniques. Cyclic voltammetry （CV） and charge-discharge cycling performance were used to characterize its electrochemical properties. The sample possessed uniformly distributed mesopores with an average pore size of 4 nm, and the specific surface area was about 69.368 m^2/g. The results show that the reversible capacity of mesoporous LiFe0.99Mo0.01PO4/C is about 160 mAh/g at 0.1C, 135 mAh/g at 1C and 90 mAh/g at 5C, respectively. The capacity fading is neglectable.展开更多
This work presents a synthesis of bimetallic NiMo and NiW modified ZSM-5/MCM-41 composites and their heterogeneous catalytic conversion of crude palm oil( CPO) to biofuels. The ZSM-5/MCM-41 composites were synthesized...This work presents a synthesis of bimetallic NiMo and NiW modified ZSM-5/MCM-41 composites and their heterogeneous catalytic conversion of crude palm oil( CPO) to biofuels. The ZSM-5/MCM-41 composites were synthesized through a self-assembly of cetyltrimethylammonium bromide( CTAB) surfactant with silica-alumina from ZSM-5 zeolite,prepared from natural kaolin by the hydrothermal technique. Subsequently,the synthesized composites were deposited with bimetallic NiMo and NiW by impregnation method. The obtained catalysts presented a micro-mesoporous structure,confirmed by XRD,SEM,TEM,EDX,NH_3-TPD,XRF and N_2 adsorption-desorption measurements. The results of CPO conversion demonstrate that the catalytic activity of the synthesized catalysts decreases in the series of NiMo-ZSM-5/MCM-41 > NiW-ZSM-5/MCM-41 > Ni-ZSM-5/MCM-41 > Mo-ZSM-5/MCM-41 > W-ZSM-5/MCM-41 > NiMo-ZSM-5 > NiW-ZSM-5 > ZSM-5/MCM-41 > ZSM-5 > MCM-41. It was found that the bimetallic NiMo-and NiW-ZSM-5/MCM-41 catalysts give higher yields of liquid hydrocarbons than other catalysts at a given conversion. Types of hydrocarbon in liquid products,identified by simulated distillation gas chromatography-flame ionization detector( SimDis GC-FID),are gasoline( 150-200 ℃; C5-12),kerosene( 250-300 ℃; C5-20) and diesel( 350 ℃; C7-20).Moreover,the conversion of CPO to biofuel products using the NiMo-and NiW-ZSM-5/MCM-41 catalysts offers no statistically significant difference( P> 0.05) at 95% confidence level,evaluated by SPSS analysis.展开更多
Goal: Low wolfram-containing cutting composite was obtained by fusion of titanium carbonitride and high melting temperature binding metallic phase. Method: The composite was obtained via compaction and further sinteri...Goal: Low wolfram-containing cutting composite was obtained by fusion of titanium carbonitride and high melting temperature binding metallic phase. Method: The composite was obtained via compaction and further sintering in vacuum furnace at 1600°C under 10<sup>-3</sup> Pa pressure. Phase analysis was performed on X-ray apparatus “DRON-3”;microstructure was determined by electron microscope NANOLAB-7, microhardness by MUCKE-mark microhardness meter;relative resistance of cutters was evaluated at similar modes of cutting according to distances they passed;experiments were carried out on turning lathe. Results: Physical-mechanical characteristics of the obtained composite are: σ<sub>bend</sub>, = 1000 - 1150 MPa, σ<sub>bend1000</sub>°C = 600 MPa, HV = 14 GPa;HV<sub>1000</sub>°C = 6.5 GPa. High speeds of cutting and high temperatures resistance of cutters made by the obtained composites exceeds 1.5 - 2-folds that of cutters made of the known BK8 and KNT20 hard alloys. Conclusion: Its application is recommended in hot steel treatment by cutting, for removal of the so-called burrs, as well as in steel treatment by cutting during pure and semi-pure operations. It can also be used in jet engines, chemical industry apparatuses, electric-vacuum devices, in industry of responsible details of rockets, nuclear reactors, flying apparatuses.展开更多
Adsorption of pure CO_(2) and N2 and separation of CO_(2)/N2 mixture in MFI zeolite and MFI/MCM-41 micro/mesoporous composite have been studied by using atomistic simulations.Fully atomistic models of MFI and MFI/MCM-...Adsorption of pure CO_(2) and N2 and separation of CO_(2)/N2 mixture in MFI zeolite and MFI/MCM-41 micro/mesoporous composite have been studied by using atomistic simulations.Fully atomistic models of MFI and MFI/MCM-41 are constructed and characterized.A bimodal pore size distribution is observed in MFI/MCM-41 from simulated small-and broad-angle X-ray diffrac-tion patterns.The density of MFI/MCM-41 is lower than MFI,while its free volume and specific surface area are greater than MFI due to the presence of mesopores.CO_(2) is preferentially adsorbed than N2,and thus,the loading and isosteric heat of CO_(2) are greater than N2 in both MFI and MFI/MCM-41.CO_(2) isotherm in MFI/MCM-41 is similar to that in MFI at low pressures,but resembles that in MCM-41 at high pressures.N2 shows similar amount of loading in MFI,MCM-41 and MFI/MCM-41.The selectivity of CO_(2) over N2 in the three adsorbents decreases in the order of MFI>MFI/MCM-41>MCM-41.With increasing pressure,the selectivity increases in MFI and MFI/MCM-41,but decreases in MCM-41.The self-diffusivity of CO_(2) and N2 in MFI decreases as loading increases,while in MFI/MCM-41,itfirst increases and then drops.展开更多
The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materia...The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.展开更多
Transition metal sulfides (TMSs) have a wide range of applications owing to their intriguing properties.Significant efforts have been devoted to nanostructuring TMSs to enhance their properties and performance,still t...Transition metal sulfides (TMSs) have a wide range of applications owing to their intriguing properties.Significant efforts have been devoted to nanostructuring TMSs to enhance their properties and performance,still there is a high need in general synthesis of TMS nanostructures.Herein,for the first time,a simple solvent free reactive nanocasting approach that integrates solid precursor loading,in-situ sulfuration and carbonization into a single heating step is developed for the universal synthesis of ordered mesoporous TMS@N-doped carbon composites (denoted as OM-TMS@NCs) with methionine (Met) and metal chlorides as the precursors and the mesoporous silica (SBA-15) as the hard template.A series of OM-TMS@NCs with a hexagonal mesostructure,ultra-high surface areas (430-754 m2·g-1),large pore volumes (0.85-1.32 cm3·g-1),and unique TMS stoichiometries,including MoS2,Fe7S8,Co9S8,NiS,Cu7S4 and ZnS,are obtained.Two distinct structure configurations,namely,highly dispersed ultrathin TMS nanosheets within NCs and TMS@NC co-nanowire arrays,can be obtained depending on different metals.The structure evolution of the OM-TMS@NCs over the solvent-free nanocasting process is studied in detail for a deep understanding of the synthesis.As demonstrations,these materials are promising for electrocatalytic hydrogen evolution reaction and lithium ion storage with high performances.展开更多
Spherical mesoporous ZrO_(2)-Al_(2)O_(3) composites containing different zirconia content have been synthesized by an oil-column sol-gel method.A mixed alumina-zirconia hydrosol and hexamethylenetetramine solution wer...Spherical mesoporous ZrO_(2)-Al_(2)O_(3) composites containing different zirconia content have been synthesized by an oil-column sol-gel method.A mixed alumina-zirconia hydrosol and hexamethylenetetramine solution were mixed together and added dropwise into a hot oil column.Due to the surface tension,spherical gel particles were formed in the oil column.The spherical gel particles were then aged and washed by deionized water and dried at 120 ℃ for 12 h and then calcined at 600 ℃ for 8 h,960 ℃ for 8 h or 1200 ℃ for 12 h.X-ray diffraction and nitrogen adsorption-desorption measurements indicated that the presence of zirconia prevents the sintering of alumina and the obtained ZrO_(2)-Al_(2)O_(3) composites have much larger surface areas than pure alumina.Temperature-programmed desorption of ammonia results illustrated that the addition of zirconia leads to an increase in the number of strong acid sites and the total number of acid sites compared with pure alumina.Thus,the spherical mesoporous ZrO_(2)-Al_(2)O_(3) composites prepared in this way were shown to be suitable for high temperature catalytic processes as a catalyst support.展开更多
This paper briefly introduces the characteristics of electron beam physical vapor depo-sition (EBPVD) technique and the whole process of preparing micro--layer compositelaminate. And several major influencing factors ...This paper briefly introduces the characteristics of electron beam physical vapor depo-sition (EBPVD) technique and the whole process of preparing micro--layer compositelaminate. And several major influencing factors are presented and discussed. It wasfound that residual gas pressure should be low enough to guarantee the unobstructedtransporfation of vapor steam and electron beam; the evaporation method and evapo-ration speed are up to the different vapor pressure deficit of compositions of raw mate-rials; and the substrate temperature could have great influence on the microstructureof the micro--layer laminates.展开更多
文摘A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods. Evaluation of catalytic activity of both the commercial Y-zeolite and the novel Y-zeolite-containing composite material was carried out in the pulse micro-chromatography platform with two probe molecules of different molecular sizes： VGO feedstock and 1,3,5 tri-isopropyl benzene. It was found that the Y-zeolite-containing composite material was richer in external surface and meso-/macro-pores; the Y-zeolite-containing composite material demonstrated a smaller rate of deactivation compared to the commercial Y-zeolite.
文摘The lanthanum aluminum mesoporous materials were synthesized using sodium dodecyl sulfate as a template agent by ultrasonic hydrothermal method.The resulting samples were characterized by low angle X-ray diffraction（XRD）,N2 adsorption-desorption studies,transmission electron microscopy（TEM）and surface morphology analysis（SEM）,surface acid（NH3-TPD）,reducibility properties（TPR）,X-ray energy dispersive spectrometer（EDS）and thermogravimetric analysis（TG/DTG）.A l/La composite mesoporous material were synthesized with n（Al）︰n（La）=70︰1.0,80°C of reaction temperature,20 h of reaction time,12 h of crystallization time,650°C of calcination temperature.The specific surface area of the sample is 273.90 m 2 ·g ？1 ,with the average diameter 5.642 nm and pore volume 0.2354 cm 3 ·g ？1 .The samples have mesoporous structure and its particles are similar to a worm-shaped tubular structure.The influence of calcination temperature on the surface physical and chemical properties of Al/La composited mesoporous materials was examined,and the results showed that the acid strength was increased but the amount of acidic sites is decreased as the calcination temperature increased.It was found that the sample calcined at 650°C had appropriate acid content,acid strength and better reducibility.
基金supported by Beijing Natural Science Foundation (No. 207001)the Funding Project for Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing Munici-pality, and the Major State Basic Research Development Program of China (No. 2002CB211807)+1 种基金supported partly by the National Out-standing Youth Fund of China (No. 10125523 to Z.W.)the Knowledge Innovation Program of Chinese Academy of Sciences (KJCX2-SW-N11, KJCX2-SW -H12-02)
文摘A mesoporous LiFe0.99Mo0.01PO4/C composite was synthesized by the sol-gel method using （NH4）2MoO4 as a doping starting material. The formation of conductive carbon, metal doping and mesopores was achieved simultaneously in the prepared material. The characterizations of crystal structures and microstructures were investigated using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, extended X-ray-absorption fine-structure （EXAFS） and X-ray-absorption near-structure spectroscopy （XANES） while the surface area was determined using N2 adsorption techniques. Cyclic voltammetry （CV） and charge-discharge cycling performance were used to characterize its electrochemical properties. The sample possessed uniformly distributed mesopores with an average pore size of 4 nm, and the specific surface area was about 69.368 m^2/g. The results show that the reversible capacity of mesoporous LiFe0.99Mo0.01PO4/C is about 160 mAh/g at 0.1C, 135 mAh/g at 1C and 90 mAh/g at 5C, respectively. The capacity fading is neglectable.
基金The financial supported by Nakhon Ratchasima Rajabhat University,Nakhon Ratchasimathe National Research Council of Thailand+3 种基金Center of Excellence for Innovation in Chemistry (PERCH-CIC)Office of the Higher Education CommissionMinistry of Education and Materials Chemistry Research CenterDepartment of Chemistry Faculty of Science,Khon Kaen University,Thailand
文摘This work presents a synthesis of bimetallic NiMo and NiW modified ZSM-5/MCM-41 composites and their heterogeneous catalytic conversion of crude palm oil( CPO) to biofuels. The ZSM-5/MCM-41 composites were synthesized through a self-assembly of cetyltrimethylammonium bromide( CTAB) surfactant with silica-alumina from ZSM-5 zeolite,prepared from natural kaolin by the hydrothermal technique. Subsequently,the synthesized composites were deposited with bimetallic NiMo and NiW by impregnation method. The obtained catalysts presented a micro-mesoporous structure,confirmed by XRD,SEM,TEM,EDX,NH_3-TPD,XRF and N_2 adsorption-desorption measurements. The results of CPO conversion demonstrate that the catalytic activity of the synthesized catalysts decreases in the series of NiMo-ZSM-5/MCM-41 > NiW-ZSM-5/MCM-41 > Ni-ZSM-5/MCM-41 > Mo-ZSM-5/MCM-41 > W-ZSM-5/MCM-41 > NiMo-ZSM-5 > NiW-ZSM-5 > ZSM-5/MCM-41 > ZSM-5 > MCM-41. It was found that the bimetallic NiMo-and NiW-ZSM-5/MCM-41 catalysts give higher yields of liquid hydrocarbons than other catalysts at a given conversion. Types of hydrocarbon in liquid products,identified by simulated distillation gas chromatography-flame ionization detector( SimDis GC-FID),are gasoline( 150-200 ℃; C5-12),kerosene( 250-300 ℃; C5-20) and diesel( 350 ℃; C7-20).Moreover,the conversion of CPO to biofuel products using the NiMo-and NiW-ZSM-5/MCM-41 catalysts offers no statistically significant difference( P> 0.05) at 95% confidence level,evaluated by SPSS analysis.
文摘Goal: Low wolfram-containing cutting composite was obtained by fusion of titanium carbonitride and high melting temperature binding metallic phase. Method: The composite was obtained via compaction and further sintering in vacuum furnace at 1600°C under 10<sup>-3</sup> Pa pressure. Phase analysis was performed on X-ray apparatus “DRON-3”;microstructure was determined by electron microscope NANOLAB-7, microhardness by MUCKE-mark microhardness meter;relative resistance of cutters was evaluated at similar modes of cutting according to distances they passed;experiments were carried out on turning lathe. Results: Physical-mechanical characteristics of the obtained composite are: σ<sub>bend</sub>, = 1000 - 1150 MPa, σ<sub>bend1000</sub>°C = 600 MPa, HV = 14 GPa;HV<sub>1000</sub>°C = 6.5 GPa. High speeds of cutting and high temperatures resistance of cutters made by the obtained composites exceeds 1.5 - 2-folds that of cutters made of the known BK8 and KNT20 hard alloys. Conclusion: Its application is recommended in hot steel treatment by cutting, for removal of the so-called burrs, as well as in steel treatment by cutting during pure and semi-pure operations. It can also be used in jet engines, chemical industry apparatuses, electric-vacuum devices, in industry of responsible details of rockets, nuclear reactors, flying apparatuses.
基金supported by the National Natural Science Foundation of China(Grant Nos.20736002,20776045)the National High Technology Research and Development Program of China(No.2008AA062302)+1 种基金Program for Changjiang Scholars and Innovative Research Team in University of China(No.IRT0721)the 111 Project of China(No.B08021).
文摘Adsorption of pure CO_(2) and N2 and separation of CO_(2)/N2 mixture in MFI zeolite and MFI/MCM-41 micro/mesoporous composite have been studied by using atomistic simulations.Fully atomistic models of MFI and MFI/MCM-41 are constructed and characterized.A bimodal pore size distribution is observed in MFI/MCM-41 from simulated small-and broad-angle X-ray diffrac-tion patterns.The density of MFI/MCM-41 is lower than MFI,while its free volume and specific surface area are greater than MFI due to the presence of mesopores.CO_(2) is preferentially adsorbed than N2,and thus,the loading and isosteric heat of CO_(2) are greater than N2 in both MFI and MFI/MCM-41.CO_(2) isotherm in MFI/MCM-41 is similar to that in MFI at low pressures,but resembles that in MCM-41 at high pressures.N2 shows similar amount of loading in MFI,MCM-41 and MFI/MCM-41.The selectivity of CO_(2) over N2 in the three adsorbents decreases in the order of MFI>MFI/MCM-41>MCM-41.With increasing pressure,the selectivity increases in MFI and MFI/MCM-41,but decreases in MCM-41.The self-diffusivity of CO_(2) and N2 in MFI decreases as loading increases,while in MFI/MCM-41,itfirst increases and then drops.
基金Projects(51134007,21003161,21250110060) supported by the National Natural Science Foundation of ChinaProject(11MX10) supported by Central South University Annual Mittal-Founded Innovation ProjectProject(2011ssxt086) supported by Fundamental Research Funds for the Central Universities,China
文摘The recent advancement in the design,synthesis,and fabrication of micro/nano structured LiNixCoyMnzO2 with one-,two-,and three-dimensional morphologies was reviewed.The major goal is to highlight LiNixCoyMnzO2 materials,which have been utilized in lithium ion batteries with enhanced energy and power density,high energy efficiency,superior rate capability and excellent cycling stability resulting from the doping,surface coating,nanocomposites and nano-architecturing.
基金Financial supports from the National Natural Science Foundation of China(Nos.21875153 and 21501125)the Natural Science Foundation of Jiangsu Province(No.BK20150312)+1 种基金the Suzhou Bureau of Science and Technology(No.SYG201637)are much appreciatedWe also thank the Young Thousand Talented Program(2015)of China,the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions and the Project of Scientific and Technologic Infrastructure of Suzhou(No.SZS201708)for supports.
文摘Transition metal sulfides (TMSs) have a wide range of applications owing to their intriguing properties.Significant efforts have been devoted to nanostructuring TMSs to enhance their properties and performance,still there is a high need in general synthesis of TMS nanostructures.Herein,for the first time,a simple solvent free reactive nanocasting approach that integrates solid precursor loading,in-situ sulfuration and carbonization into a single heating step is developed for the universal synthesis of ordered mesoporous TMS@N-doped carbon composites (denoted as OM-TMS@NCs) with methionine (Met) and metal chlorides as the precursors and the mesoporous silica (SBA-15) as the hard template.A series of OM-TMS@NCs with a hexagonal mesostructure,ultra-high surface areas (430-754 m2·g-1),large pore volumes (0.85-1.32 cm3·g-1),and unique TMS stoichiometries,including MoS2,Fe7S8,Co9S8,NiS,Cu7S4 and ZnS,are obtained.Two distinct structure configurations,namely,highly dispersed ultrathin TMS nanosheets within NCs and TMS@NC co-nanowire arrays,can be obtained depending on different metals.The structure evolution of the OM-TMS@NCs over the solvent-free nanocasting process is studied in detail for a deep understanding of the synthesis.As demonstrations,these materials are promising for electrocatalytic hydrogen evolution reaction and lithium ion storage with high performances.
基金supported by the National Natural Science Foundation of Chinathe 111 Project (B07004)the Program for Changjiang Scholars and Innovative Research Teams in Universities (IRT0406)
文摘Spherical mesoporous ZrO_(2)-Al_(2)O_(3) composites containing different zirconia content have been synthesized by an oil-column sol-gel method.A mixed alumina-zirconia hydrosol and hexamethylenetetramine solution were mixed together and added dropwise into a hot oil column.Due to the surface tension,spherical gel particles were formed in the oil column.The spherical gel particles were then aged and washed by deionized water and dried at 120 ℃ for 12 h and then calcined at 600 ℃ for 8 h,960 ℃ for 8 h or 1200 ℃ for 12 h.X-ray diffraction and nitrogen adsorption-desorption measurements indicated that the presence of zirconia prevents the sintering of alumina and the obtained ZrO_(2)-Al_(2)O_(3) composites have much larger surface areas than pure alumina.Temperature-programmed desorption of ammonia results illustrated that the addition of zirconia leads to an increase in the number of strong acid sites and the total number of acid sites compared with pure alumina.Thus,the spherical mesoporous ZrO_(2)-Al_(2)O_(3) composites prepared in this way were shown to be suitable for high temperature catalytic processes as a catalyst support.
基金This work was supported by the Natural Science Foundation of Heilongjiang Province(No.E01-07)Postdoctoral Science Foundation of China(No.LB0047).
文摘This paper briefly introduces the characteristics of electron beam physical vapor depo-sition (EBPVD) technique and the whole process of preparing micro--layer compositelaminate. And several major influencing factors are presented and discussed. It wasfound that residual gas pressure should be low enough to guarantee the unobstructedtransporfation of vapor steam and electron beam; the evaporation method and evapo-ration speed are up to the different vapor pressure deficit of compositions of raw mate-rials; and the substrate temperature could have great influence on the microstructureof the micro--layer laminates.
