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 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
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
随着军事和民用技术的快速发展,对航空、户外等领域所用器件在复杂环境下的稳定性提出了更为严格的要求。这些器件经常需要在较大的温度变化范围内工作,而温度变化所带来的材料体积变化是器件结构受损,功能失效的重要原因之一。因此,如...随着军事和民用技术的快速发展,对航空、户外等领域所用器件在复杂环境下的稳定性提出了更为严格的要求。这些器件经常需要在较大的温度变化范围内工作,而温度变化所带来的材料体积变化是器件结构受损,功能失效的重要原因之一。因此,如航空航天设备中所用的精密结构件不仅需要具有优秀的导电、导热性能,还需要保证其在温度变化过程中具有较低的热膨胀系数。因此,研究制备具有近零膨胀性能的材料便成为解决这些问题的重要方法之一。在本研究中,作者通过改变烧结温度,制备出一系列介孔铁电PbTiO_(3)(PTO)陶瓷,通过测试结果展示了材料的热导率、热膨胀系数与烧结温度的关系。进一步通过三维重构技术(Tomography)与高角度环形暗场像(high angle annular dark field,HAADF),分析了改变烧结温度对于介孔尺寸、分布密度的影响,以及单个介孔表面附近的铁电屏蔽效应影响范围,从而解释了烧结温度的变化与介孔的分布密度、尺寸大小以及热膨胀行为之间的紧密联系。随着烧结温度的降低,介孔对材料铁电屏蔽效应的总区域占比逐渐升高,从而使材料正膨胀系数增大,导致材料表现出近零膨胀。为进一步提高材料的热导率,提升材料的多功能性,将这一材料与石墨烯进行复合,通过改变烧结温度与石墨烯的复合比例,进一步使材料的热膨胀系数趋近于零膨胀,并通过调整烧结温度与复合比例,得到膨胀系数低至7×10^(-7)℃^(-1),热导率比单相陶瓷提升约65%的近零膨胀复合陶瓷。这种材料可以在芯片封装,航天器外壳,通讯设备等材料领域得到进一步广泛应用的空间。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
Silver nanoparticles were prepared in the channels of mesoporous silica SBA-15 through silver mirror reaction.The results of X-ray diffraction(XRD) and transmission electron microscopy(TEM) reveal that Ag nanoparticle...Silver nanoparticles were prepared in the channels of mesoporous silica SBA-15 through silver mirror reaction.The results of X-ray diffraction(XRD) and transmission electron microscopy(TEM) reveal that Ag nanoparticles with uniform size about 2-3 nm were dispersed inside the channels of mesoporous SBA-15.UV-Vis absorption spectra indicate the quantum size effect of the Ag nanoparticles.Bacteriological tests were performed in Luria-Bertani(LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of Ag/SBA-15.This nanocomposite was shown to be an effective bactericide against Staphylococcus.展开更多
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.
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.
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.
文摘随着军事和民用技术的快速发展,对航空、户外等领域所用器件在复杂环境下的稳定性提出了更为严格的要求。这些器件经常需要在较大的温度变化范围内工作,而温度变化所带来的材料体积变化是器件结构受损,功能失效的重要原因之一。因此,如航空航天设备中所用的精密结构件不仅需要具有优秀的导电、导热性能,还需要保证其在温度变化过程中具有较低的热膨胀系数。因此,研究制备具有近零膨胀性能的材料便成为解决这些问题的重要方法之一。在本研究中,作者通过改变烧结温度,制备出一系列介孔铁电PbTiO_(3)(PTO)陶瓷,通过测试结果展示了材料的热导率、热膨胀系数与烧结温度的关系。进一步通过三维重构技术(Tomography)与高角度环形暗场像(high angle annular dark field,HAADF),分析了改变烧结温度对于介孔尺寸、分布密度的影响,以及单个介孔表面附近的铁电屏蔽效应影响范围,从而解释了烧结温度的变化与介孔的分布密度、尺寸大小以及热膨胀行为之间的紧密联系。随着烧结温度的降低,介孔对材料铁电屏蔽效应的总区域占比逐渐升高,从而使材料正膨胀系数增大,导致材料表现出近零膨胀。为进一步提高材料的热导率,提升材料的多功能性,将这一材料与石墨烯进行复合,通过改变烧结温度与石墨烯的复合比例,进一步使材料的热膨胀系数趋近于零膨胀,并通过调整烧结温度与复合比例,得到膨胀系数低至7×10^(-7)℃^(-1),热导率比单相陶瓷提升约65%的近零膨胀复合陶瓷。这种材料可以在芯片封装,航天器外壳,通讯设备等材料领域得到进一步广泛应用的空间。
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.
文摘Silver nanoparticles were prepared in the channels of mesoporous silica SBA-15 through silver mirror reaction.The results of X-ray diffraction(XRD) and transmission electron microscopy(TEM) reveal that Ag nanoparticles with uniform size about 2-3 nm were dispersed inside the channels of mesoporous SBA-15.UV-Vis absorption spectra indicate the quantum size effect of the Ag nanoparticles.Bacteriological tests were performed in Luria-Bertani(LB) medium on solid agar plates and in liquid systems supplemented with different concentrations of Ag/SBA-15.This nanocomposite was shown to be an effective bactericide against Staphylococcus.
