α-MnO2纳米线的制备及其电化学性能研究

以KMnO4为锰源,采用水热反应在HCl溶液中制备α-MnO2纳米线.探讨了水热反应温度、水热反应时间等对α-MnO2纳米线合成的影响,对制备产物进行了XRD和SEM分析,并初步探索了α-MnO2的电化学性质.结果表明:最佳水热反应时间为24 h、最佳水热反应温度为240℃;α-MnO2纳米线具有良好的电容性能,在1....     

不同形貌二氧化锰的制备及其电化学性能研究

采用水热法,在不同的水热反应温度和反应时间条件下制备了两种晶型和形貌的二氧化锰,并将之用于超级电容器电极材料。借助X射线衍射、扫描电镜、透射电镜以及比表面分析仪等测试手段对二氧化锰材料进行物理结构表征。结果表明:100℃水热反应12 h的产品为纳米片状的δ-MnO_2,其BET比表面积为23.2 m2/g;200℃水热反应36 h的产品为纳米线状的α-MnO_2,其BET比表面积为14.6 m2/g。通过循环伏安、恒电流充放电和电化学阻抗研究了二氧化锰材料的电化学行为。结果表明:δ-MnO_2纳米片的循环伏安曲线比α-MnO_2纳米线电极更接近于矩形;在0.5 A/g电流密度下,δ-MnO_2纳米片的比电容高达283.5 F/g,而α-MnO_2纳米线只有227.5 F/g。     

Ce~(3+)掺杂片状Sr_2MgSi_2O_7的合成及发光性能(英文)

采用水热合成技术在不锈钢反应釜中制备铈离子掺杂硅酸盐基发光材料。通过X射线衍射、扫描电子显微镜表征产物的晶体结构、形貌及尺寸,并讨论硅酸镁锶晶体水热反应过程。结果表明:经220℃水热反应48h可形成硅酸镁锶相,水热反应产物经800℃保温2h和6h的热处理可明显提高产物中硅酸镁锶相含量。采用荧光光谱仪测试不同温度处理铈离子掺杂硅酸镁锶的光致发光性能,光源为氙灯,经氢气处理后样品中存在唯一波长位于371nm的紫外发光,该发光带激发光谱由3个发光峰组成,波长分别为262、287nm和317nm,该紫外发光强度随热处理温度上升而提高。     

焙烧温度对碳纳米管钴基费托合成催化剂的影响

通过浸渍法制备了不同焙烧温度的碳纳米管钴基费托合成催化剂[CAT(X),X=250、300、350、400、450、500],利用热重分析、氮气物理吸附-脱附、X射线衍射、氢气程序升温还原、扫描电镜、透射电镜和X射线光电子能谱等考察了焙烧温度对催化剂热稳定性、结构、物相、还原度及费托合成反应性能的影响。结果表明:载体碳纳米管在500℃以下可以稳定存在;焙烧温度在250~500℃时,催化剂的比表面积在79.78~85.23 m2/g,孔容在0.60~0.68 m3/g,孔径在28.9~33.4 nm。其中,经350℃焙烧的催化剂CAT(350)比表面积为79.78 m2/g,孔容为0.67 m3/g,孔径为33.4 nm;在350℃焙烧后,催化剂表面钴主要有Co3O4和Co O两种存在形式,晶粒细小,尺寸分布窄。程序升温还原测试和费托合成反应性能评价结果显示,350℃焙烧的催化剂CAT(350)还原温度最低,一氧化碳转化率最高,为12.5%。     

碳纳米管负载NiCo催化剂的制备及析氧性能研究

以碳纳米管(CNTs)为载体,通过调控水热反应时间及温度负载NiCo颗粒,制备NiCo/CNTs复合催化剂。利用碳纳米管独特的中空管状结构、高比表面积以及良好的导电特性来负载高活性的NiCo颗粒,开发高性能析氧催化剂。利用激光拉曼、扫描电子显微镜、X射线衍射和电化学测试研究了水热反应温度与时间对NiCo/CNTs复合催化剂形貌、晶型结构及电化学性能的影响。结果表明,在130℃、24 h与150℃、8 h条件下制备的NiCo/CNTs复合催化剂的综合性能较为优异。     

焙烧温度对碳纳米管钴基费托合成催化剂性能的影响

通过浸渍法制备了不同焙烧温度的碳纳米管钴基费托合成催化剂[CAT(X),X=250、300、350、400、450、500],利用热重分析、氮气物理吸附-脱附、X射线衍射、氢气程序升温还原、扫描电镜、透射电镜和X射线光电子能谱等考察了焙烧温度对催化剂热稳定性、结构、物相、还原度及费托合成反应性能的影响。结果表明:载体碳纳米管在500℃以下可以稳定存在;焙烧温度在250~500℃时,催化剂的比表面积在79.78~85.23 m2/g,孔容在0.60~0.68 m3/g,孔径在28.9~33.4 nm。其中,经350℃焙烧的催化剂CAT(350)比表面积为79.78 m2/g,孔容为0.67 m3/g,孔径为33.4 nm;在350℃焙烧后,催化剂表面钴主要有Co3O4和Co O两种存在形式,晶粒细小,尺寸分布窄。程序升温还原测试和费托合成反应性能评价结果显示,350℃焙烧的催化剂CAT(350)还原温度最低,一氧化碳转化率最高,为12.5%。     

钛酸锂纳米管的制备工艺研究

采用钛酸纳米管为原料,通过水热离子交换反应工艺制备钛酸锂纳米管,考察了水热反应温度、离子浓度以及热处理温度对纳米管结构形貌的影响。研究表明,反应中0.5mol·L-1的离子浓度以及120℃的反应温度可制得形貌较好的钛酸锂纳米管前驱体,而350℃既是最佳处理温度又是钛酸锂纳米管转变成纳米线棒的临界温度。     

水热法制备钒酸铋及其光催化性能研究

采用水热法制备了钒酸铋催化剂，以罗丹明B为目标降解物，对催化剂的光催化性能进行了测定。考察了水热反应pH、反应温度、反应时间对催化剂光催化性能的影响，实验得出制备钒酸铋催化剂的最佳水热反应条件：水热反应pH为7、反应温度为100℃、反应时间为8 h。在最佳水热反应条件下，投放5 mg的钒酸铋催化剂，对5 mL初始质量浓度为10 mg/L罗丹明B溶液的光催化降解率高达96.5%。最后利用X射线衍射（XRD）表征手法，对最佳水热反应条件下制备的钒酸铋催化剂的结构进行了表征，证明制得的钒酸铋催化剂纯度较高。     

Cu_2O@ Cu纳米线的制备及对染料废水的脱色效能

利用化学沉积法制备铜纳米线,以铜纳米线为基质,在不同温度下水浴反应合成具有核壳结构的一维Cu_2O@ Cu纳米线。利用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)、比表面积测试(BET)、紫外-可见光谱(UV-VISDRS)等分析手段,对所得材料的结构、形貌和光学性质进行表征。并考察了其对甲基橙的吸附性能和光催化性能。结果表明:合成的Cu_2O@ Cu纳米线对甲基橙取得了71.4%的吸附率和70.1%光催化脱色率,且Cu_2O@ Cu纳米线表面的纳米Cu_2O粒径过大或过小都将减弱其脱色性能,结晶性越好可增强其脱色性能,其粒径在30~34 nm范围内,脱色效能最佳。     

Fe21Ni79合金纳米线阵列的制备与磁性

用交流电化学沉积方法,在多孔铝阳极氧化膜的柱形孔内制备直径约60 nm,长度约为9.7 μm的Fe₂₁Ni₇₉合金纳米线.采用扫描电镜、透射电镜、X射线衍射仪和振动样品磁强计对纳米线的形貌 、结构和磁学性质进行了测试.结果表明,Fe₂₁Ni₇₉纳米线排列有序,长径比可控,合金呈fcc结构.当将其在外磁场下进行垂直磁化时,磁滞回线出现较高的矩形比0.86,矫顽力达1203Oe.且随着退火温度升高,矫顽力迅速增大,500℃时达到最大值1315Oe,之后又随退火温度的升高而下降.矩形比也呈现类似的变化规律.     

Influence of microwave-assisted hydrothermal treatment time on the crystallinity,morphology and optical properties of ZnWO4 nanoparticles: Photocatalytic activity

In this work, zinc tungstate (ZnWO₄) nanoparticles were obtained by microwave-assisted hydrothermal method at 140 °C and 2 atm. The hydrothermal treatment time was varied at 0, 5, 10, 30, 60 and 120 min. The nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscope (TEM), high-resolution transmission electron microscope (HRTEM), X-ray fluorescence (FRX), nitrogen adsorption by Brunauer-Emmett-Teller method (BET), UV–Visible spectroscopy (UV–Vis) and Photoluminescence (PL) properties. The adsorptive and photocatalytic properties were estimated against methylene blue (MB - cationic) and methyl orange (MO - anionic) dyes. The diffractograms show that the larger hydrothermal treatment time, anhigher the powders crystallinity. The BET and SEM analysis indicate that the increase in hydrothermal time does not interfere significantly in nanoparticles size but reduces their porosity. The change in the surface area is consistent with the adsorption tests, where the increase of the hydrothermal treatment time reduces the adsorption against the MB and MO dyes. However, increasing the hydrothermal treatment time provides an increase in photocatalytic activity.     

介孔ZrO2/SnO2催化剂的合成与表征

以表面活性剂十六烷基三甲基溴化铵的水溶液所形成的柱状胶束为模板,ZrOCl2·8H2O,SnCl4·5H2O为原料,合成具有介孔结构的ZrO2/SnPO2复合催化剂.通过X射线衍射、场发射扫描电镜及氮气吸附等温线等的测定,研究ZrO2/SnO2复合催化剂的孔结构.结果表明:合成得到的复合催化剂具有介孔结构.用BET(Brunauer-Emmett-Teller)法计算得到的产物比表面积为190.2 m2/g.由BJH(Barret-Joyner-Halenda)法计算的介孔大小平均值为17.04nm.     

以工业钛液为原料低温制备锐钛矿型纳米二氧化钛(英文)

以工业钛液为原料,在常温常压下制备了锐钛矿型纳米二氧化钛粉体。用X射线衍射、高分辨率电镜、激光散射粒径分析、BET(Brunauer-Emmett-Teller)比表面积分析、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)和扫描电镜等对粉体进行了表征,研究了硝酸浓度和反应时间对粒径大小的影响。结果表明:制备的纳米二氧化钛呈球形,平均粒径小于10nm,粒径分布窄,结晶良好,BET比表面积为139.57m2/g。样品中的聚集体为近似球形,其尺寸为35nm。XPS分析表明:在纳米二氧化钛颗粒表面不仅包括钛、氧和碳元素,还包括氮、铁和硫元素。     

Preparation, Characterization, and Photocatalytic Properties of CaNb2O6 Nanoparticles

CaNb₂O₆ nanoparticles with a size range of 30–50 nm were synthesized by heat treatment at 600°C after a solvothermal process and their optical and photocatalytic properties were investigated. The prepared powders were characterized by X-ray powder diffractometer, field-emission scanning electron microscope, transmission electron microscope, UV-Vis diffuse reflectance spectroscopy, Fluorescence spectroscopy, and Raman spectroscopy. Compared with a powder of the same material prepared by a solid-state reaction (SS) method, the nanoparticles exhibited a higher Brunauer–Emmett–Teller (BET) surface area, more efficient light absorption, and enhanced photocatalytic activity for producing H₂ from pure water under UV irradiation. The photoluminescence spectra revealed that a radiative recombination process is dominant in the powder prepared by the SS method (strong blue emission at 300 K) under UV light irradiation, while no obvious emission was observed in the nanoparticles. This decrease of the radiative recombination as well as the higher optical absorption ability and higher BET surface area resulting from the reduced dimensionality led to enhanced photocatalytic activity of the nanoparticles.     

花状NiO纳米片自组装体的制备与表征

以硝酸镍、尿素为原料,在醇-水介质中,85℃恒温条件下,用均匀沉淀法制备出花状纳米片自组装结构Ni(OH)_2沉淀,该沉淀经400℃煅烧制得具有花状形貌的NiO纳米片自组装体.采用X射线衍射、扫描电镜、透射电镜、Fourier变换红外光谱、Brunauer-Ennett-Teller(BET)比表面积方法对粉体进行表征.研究表明:该NiO粉体为六方结构,其纳米片尺寸约为2μm × 3μm,厚度约为100nm,曲面间隙约为0.8μm,具有微孔结构.BET法测得粉体的比表面积为108.66m~2/g,制得的粉体具有明显的纳米效应,Ni-O键振动峰值(403.6cm~(-1))较非纳米颗粒(487.1 cm~(-1))蓝移了84.5cm~(-1),乙醇对花状结构NiO纳米片自组装体的形成具有重要作用.分析了花状NiO纳米片自组装体的形成机理.     

熔盐体系组成对二氧化碳电化学合成新型碳材料形貌影响

以碳酸盐为电解质,以铁、镍、镍铬合金等廉价金属材料为电极,研究构建了高温熔盐电解池,将CO₂一步法转化为新型碳材料,并考察了熔盐组成及配比、电解温度、电流密度、电极材料等实验条件对碳材料形貌结构的影响。采用X射线能谱分析仪（EDS）、扫描电镜（SEM）、透射电镜（TEM）、比表面积测试仪（BET）、X射线衍射仪（XRD）及拉曼光谱仪（Raman）等手段对碳材料的元素组成、形貌结构、比表面积、结晶度、有序度等特性进行表征分析。研究结果表明,450～600℃温度范围内,电解多元混合熔盐体系主要生成无定形碳;同时,电解温度、电流密度、电解质组成及配比等对碳产物的比表面积具有明显影响;通过改变电解质体系,辅以调控电流密度及电解温度等实验参数,可实现碳纳米管、碳球及蜂窝状多孔碳等特定形貌碳材料的可控合成,其中碳纳米管的石墨化程度较高,且由碳原子组成的层状六方石墨晶体排列规则有序。     

磁性X沸石的合成及其性能

采用水热合成法,在X型沸石的晶化原料液中加入磁核合成了磁性沸石,对合成产物进行了结构性能测试. 结果表明,产物为X型沸石结构,具有较好的磁性能和吸附性能. 饱和磁化强度为3.7 emu/g,在磁场作用下,磁性沸石在30 min内完成与母液的分离,产物的比表面积为571.5 m2/g,铅离子吸附量为196.8 mg/g.     

An Efficient Protocol for Aza-Michael Addition Reactions Under Solvent-Free Condition Employing Sulfated Zirconia Catalyst

The aza-Michael addition reactions of amines with α,β-unsaturated carbonyl compounds were efficiently carried out at room temperature under solvent-free condition employing sulfated zirconia as a reusable heterogeneous catalyst. The desired products were formed in short reaction times and in high yields. The bulk and surface properties of the synthesized catalyst was examined by X-ray powder diffraction, BET surface area, temperature programmed desorption of ammonia, scanning electron microscopy and thermogravimetric techniques. Characterization results reveal the super acidic nature of the catalyst.     

Fabrication of Nanostructured Hydroxyapatite via Hydrothermal Synthesis and Spark Plasma Sintering

Hydrothermal synthesis has been used to produce hydroxyapatite (HA) particles with high crystallinity. Such particles of nanorods were used to fabricate HA ceramic by using spark plasma sintering. X-ray diffraction, transmission electron microscope, scanning electron microscope, and the BET method have been used to examine crystallite size, crystallite shape, and the surface area of particles, and grain size of sintered HA ceramics. It was found that the morphology of the nanorods in the HA particles changed to a more equiaxed shape during sintering.     

Intercalation of 2,4-dihydroxybenzophenone-5-sulfonate anion into Zn/Al layered double hydroxides for UV absorption properties

Zn/Al-layered double hydroxides (LDHs) containing the organic anion of 2,4-dihydroxybenzophenone-5-sulfonate (DHBS) have been synthesized by co-precipitation method. Surface, structural, thermal and absorption properties of the ZnAl-DHBS-LDHs nanohybrids were characterized by BET analysis, scanning electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetry and differential thermal analysis and UV–visible spectroscopy. The results revealed that organic UV absorbent-DHBS has been intercalated into the interlayer spaces of ZnAl-LDHs and the intercalation of DHBS in LDHs interlayer galleries resulted to higher thermal stability and better UV absorption ability; these show that the hybrid ZnAl-DHBS-LDHs phase has potential applications as a UV absorber.