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1.
采用Zn-MOF(MOF为金属有机骨架)制备纳米多孔碳材料,通过自组装法将多孔碳与花状MoS2结合,制备出具有规整有序结构的花状Zn-MOF衍生碳@MoS2复合吸波材料。基于Zn-MOF衍生纳米多孔碳的高孔隙率、大比表面积,MoS2的花状结构引起的电磁波多次反射和散射,以及MoS2和Zn-MOF衍生碳之间存在的强极化效应、良好的阻抗匹配和协同作用,Zn-MOF衍生碳@MoS2在频率为9.28 GHz时的最佳反射损耗达到-49.68 dB,表现出优异的电磁波吸收性能。 相似文献
2.
由于具有高安全性和优异的循环稳定性,二氧化钛(TiO2)作为负极材料被广泛地应用于锂离子电池领域。但是较差的导电性和离子传输速率限制了TiO2的进一步应用和发展。鉴于此,我们以花状NH2-MIL-125 (Ti)为前驱体和硬模板,成功合成出了具有花状结构的超细纳米TiO2/多孔氮掺杂碳片(N-doped porous carbon)复合物(记为FL-TiO2/NPC)。过程中所制备的纳米TiO2-金属有机构架(Ti-MOF)展现出由二维褶皱多孔纳米片堆积、组装而成的花状结构。一方面,二维褶皱纳米片包含TiO2纳米颗粒可以增大活性物质与电解液的接触面积;另一方面,氮掺杂多孔碳基体可以提高整体复合物的导电性和结构完整性。将所获得的FL-TiO2/NPC作为负极组装成的锂半电池, 在0.5 A·g-1、300圈后仍有384.2 mAh·g-1以及在1 A·g-1、500圈仍有279.1 mAh·g-1的比容量。进一步性能测试表明,在2 A·g-1、2000圈长循环测试后,其仍能保持256.5 mAh·g-1的比容量和接近100%的库伦效率。该优异的电化学活性和稳定性主要起源于材料独特的花状结构。我们的合成策略为今后制备高储锂性能的金属氧化物/多孔氮掺杂碳负极提供了一种新的思路。 相似文献
3.
以废虾壳为碳源,通过惰性气氛高温碳化法制得废虾壳衍生的多孔碳纳米酶,并将其作为一种类过氧化物模拟酶用于比色检测自来水中的H2O2。所制备的碳纳米酶呈无定型多孔结构,且催化活性类似天然辣根过氧化物酶。考察了反应体系中各参数对类过氧化物酶催化活性的影响。在最优条件下,废虾壳衍生多孔碳纳米酶比色分析H2O2的线性范围为0~200μmol/L,线性相关系数R2=0.9772,检出限为0.59μmol/L。建立的方法可用于快速分析自来水中的H2O2。 相似文献
4.
通过煅烧和静电自组装的方法制备了1T′ MoS2超薄纳米片和类石墨烯相氮化碳(g-C3N4)纳米片的复合材料. 该材料在光催化实验中展现出6.24 μmol?g?1?h?1的产氢速率, 优于贵金属铂修饰的g-C3N4纳米片的性能(4.64 μmol?g?1?h?1). 此外, 该复合材料在光催化降解有机染料甲基橙的实验中表现出0.19 min?1的催化速率, 而纯g-C3N4纳米片只有0.053 min?1的催化速率. 材料光催化性能的提升可归结于1T′MoS2 和g-C3N4之间的协同效应, 包括光吸收的增强以及因1T′MoS2优异电子导电性而得到的高效电荷分离. 相似文献
5.
二硫化钼(MoS2)作为一种与石墨烯具有类似结构的材料, 近些年来受到了科学家们的越来越多的关注. 它凭借自身的层状结构, 独特的电子学、电化学性质, 大的比表面积以及表面改性的潜能, 在许多领域都有着广泛的应用. 本文简单论述了目前纳米尺寸MoS2的制备方法, 包括微机械剥离、液相剥离、嵌锂法、水热反应、气相沉积以及热分解法等, 并对这些方法在制备纳米MoS2中具备的优点和存在的不足作了简单点评. 另外, 介绍了纳米MoS2在光电子器件、催化、传感、能量存储与转化等领域的应用研究进展, 并着重介绍了其在电化学和生物传感分析方面的应用研究现状, 并对未来纳米MoS2的重点研究方向作出了展望. 从目前的研究来看, 纳米MoS2在器件、能量存储和传感分析等应用方面存在着巨大的潜质, 有望成为一种继石墨烯之后性能十分优良的多功能材料. 相似文献
6.
不同硫源水热合成的MoS催化剂的形貌和加氢脱氧活性比较研究 《燃料化学学报》2018,46(5):535-542
分别采用硫脲、L-胱氨酸和硫磺为硫源水热合成了三种MoS2催化剂,对其结构和形貌特征进行了表征,并以对甲酚为探针化合物,比较研究了三种MoS2的加氢脱氧(HDO)催化活性。结果表明,硫源对MoS2晶体结构的影响不大,但对其形貌和比表面积影响较大。与商业MoS2相比,所制备的MoS2催化剂都表现出更高的HDO活性;其中,以硫脲为原料合成的MoS2具有较高的比表面积和花状结构,其催化活性最高,在300℃下进行对甲酚的HDO反应,脱氧度可达99.3%。 相似文献
7.
二硫化钼纳米片(MoS2)受到带电杂质、结构缺陷和易聚集等因素的影响,导致其电子转移性能下降,使其应用受限。将银纳米颗粒(Ag NPs)与少层MoS2纳米片复合,可提升MoS2纳米片的电化学性能。本研究创新性地采用微波还原法,使Ag NPs原位沉积于MoS2,得到Ag NPs/MoS2复合材料。结果表明,将Ag NPs/MoS2复合材料修饰于丝网印刷电极(screen printed electrodes,SPE)后,测得的循环伏安(cyclic voltammetry,CV)曲线峰电流值为同浓度单一MoS2修饰电极的1.8倍,方波伏安(square wave voltammetry,SWV)曲线峰电流值为单一MoS2修饰电极的3.4倍,电化学阻抗谱(electrochemical impedance spectroscopy,EIS)的电子转移阻抗值(Ret)仅为167Ω,相比MoS2/S... 相似文献
8.
二维过渡族金属硫属化合物因其带隙具有强烈的层数依赖性而在电子器件方面具有广泛的应用前景.其中单层二硫化钼(MoS2)是该系列材料中最典型的一种直接带隙半导体,它具有优异的光、电、磁、热和力学性能.二维MoS2有望在光电探测、光伏器件、场效应晶体管、存储器件、谷电子和自旋器件、温差电器件、微纳机电器件和系统等方面得以广泛应用.化学气相沉积(CVD)法已成为制备二维过渡族金属硫属化合物如MoS2、MoSe2、WS2和WSe2等原子层薄膜的主要手段,尤其科学界利用CVD法对二维MoS2材料进行了深入的制备探索,通过该方法制备的MoS2薄膜在电子和光电器件方面已经有广泛研究.本文将从二维MoS2的基本物性出发,详细介绍CVD法制备MoS2的各种工艺过程,如热分解硫代硫酸盐法、硫化Mo(MoO3-x)薄膜制备法、MoO3-x粉体与硫属前驱体气相合成法和钼箔表面直接硫化法,并介绍了基于MoS2的二维异质结构筑方法.在制备材料的基础上,详细阐述了二维MoS2在场效应晶体管、光电探测器、柔性电子器件以及异质结器件方面的应用,并展望了二维材料在半导体器件中的应用前景. 相似文献
9.
通过在PPy@玉米芯多孔碳修饰的玻碳电极上沉积ZrO2纳米粒子,制备了一种灵敏检测食品中草甘膦残留的电化学传感器电极材料。玉米芯多孔碳的平均孔径为4.07 nm。PPy@玉米芯多孔碳复合材料的高比表面积增加了ZrO2的负载量。PPy@玉米芯多孔碳修饰电极用于草甘膦检测的线性范围为0.1~10μg/kg和10~1000μg/kg,检出限为24.4 ng/kg,检测稻谷中草甘膦的回收率为95.5%~99.1%。该传感器可用于实际食品样品中草甘膦残留的检测。 相似文献
10.
通过水热法合成了一系列MoS2/GQDs复合材料,并制成碳基复合电极。利用电化学测试手段挑选出最佳电极后用于微生物电解池(MEC)阴极的产氢性能研究。实验结果显示: Na2MoO4、半胱氨酸和GQDs的最佳原料配比为375:600:1,制备出的MoS2/GQDs呈现明显的爆米花样纳米片结构,片层厚度在10 nm左右,当碳纸负载量为1.5 mg·cm-2时,MoS2/GQDs碳纸电极的析氢催化能力最佳。在MEC产氢实验中,MoS2/GQDs阴极MEC的产气量、氢气产率、库仑效率、整体氢气回收率、阴极氢气回收率、电能回收率和整体能量回收率分别为51.15±3.15 mL·cycle-1、0.401±0.032 m3H2·m3d-1、91.16±0.054%、66.64±5.39%、72.44±2.60%、217.26±7.42%和77.37±1.50%,均略高于Pt/C阴极MEC或与之媲美。另外,MoS2/GQDs具有良好的长期稳定性,且价格便宜,有利于实际应用。 相似文献
11.
研究了在不同温度下的NaNO3和AgNO3水溶液中Li1.3Ti1.7Al0.3(PO4)3和Na1.3Ti1.7Al0.3(PO4)3离子交换行为.实验表明Li1.3Ti1.7Al0.3(PO4)3和Na1.3Ti1.7Al0.3(PO4)3均显示出了高选择性与Na+和Ag+进行离子交换的特征,且对Ag+的选择性高于Na+.升高温度可显著提高Ag/Li和Ag/Na的交换反应速度. 相似文献
12.
Ioana Vidican 《Journal of solid state chemistry》2003,170(2):203-210
Single crystals of K3RESi2O7 (RE=Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu) were grown from a potassium fluoride flux. Two different structure types were found for this series. Silicates containing the larger rare earths, RE=Gd, Tb, Dy, Ho, Er, Tm, Yb crystallize in a structure K3RESi2O7 that contains the rare-earth cation in both a slightly distorted octahedral and an ideal trigonal prismatic coordination environment, while in K3LuSi2O7, containing the smallest of the rare earths, lutetium is found solely in an octahedral coordination environment. The structure of K3LuSi2O7 crystallizes in space group P63/mmc with a=5.71160(10) Å and c=13.8883(6) Å. The structures containing the remaining rare earths crystallize in the space group P63/mcm with the lattice parameters of a=9.9359(2) Å, c=14.4295(4) Å, (K3GdSi2O7); a=9.88730(10) Å, c=14.3856(3) Å, (K3TbSi2O7); a=9.8673(2) Å, c=14.3572(4) Å, (K3DySi2O7); a=9.8408(3) Å, c=14.3206(6) Å, (K3HoSi2O7); a=9.82120(10) Å, c=14.2986(2) Å, (K3ErSi2O7); a=9.80200(10) Å, c=14.2863(4) Å, (K3TmSi2O7); a=9.78190(10) Å, c=14.2401(3) Å, (K3YbSi2O7). The optical properties of the silicates were investigated and K3TbSi2O7 was found to fluoresce in the visible. 相似文献
13.
The near infrared spectra of aqueous solutions of the ethylsulfates of La, Nd, Gd, Tb, Er, Yb, Lu, Y, and Na have been determined from about 0.2 mol-dm–3 to nearly saturation. The extinction coefficients of water have been calculated taking into account the absorption of ethylslfate anions determined in separate experiments. Their values appeared to be nearly the same as that of pure water. The relative contents of free OH groups in 0.5 and 0.7M solutions have been estimated from the absorbances at 1160 nm. They were lower in solutions of the heavy rare-earth ethylsulfates (Tb, Er, Yb, Lu) than in equimolar solutions of the lighter ones (La, Nd), confirming our previous view that secondary hydration of the heavy trivalent rare-earth cations is distinctly stronger than that of the lighter ones. A comparison of the spectra of these aqueous ethylsulfates with those of perchlorates shows that the structure-breaking ability of the C2H5SO
4
–
ion is much smaller than that of perchlorate anion. 相似文献
14.
The crystal structures of compounds with nominal compositions Bi6FeP2O15+x (I), Bi6NiP2O15+x (II) and Bi6ZnP2O15+x (III) were determined from single-crystal X-ray diffraction data. They are monoclinic, space group I2, Z=2. The lattice parameters for (I) are a=11.2644(7), b=5.4380(3), c=11.1440(5) Å, β=96.154(4)°; for (II) a=11.259(7), b=5.461(4), c=11.109(7) Å, β=96.65(1)°; for (III) a=19.7271(5), b=5.4376(2), c=16.9730(6) Å, β=131.932(1)°. Least squares refinements on F2 converged for (I) to R1=0.0554, wR2=0.1408; for (II) R1=0.0647, wR2=0.1697; for (III) R1=0.0385, wR2=0.1023. The crystals are complexly twinned by 2-fold rotation about , by inversion and by mirror reflection. The structures consist of edge-sharing articulations of OBi4 tetrahedra forming layers in the a-c plane that then continue by edge-sharing parallel to the b-axis. The three-dimensional networks are bridged by Fe and Ni octahedra in (I) and (II) and by Zn trigonal bipyramids in (III) as well as by oxygen atoms of the PO4 moieties. Bi also randomly occupies the octahedral sites. Oxygen vacancies exist in the structures of the three compounds due to required charge balances and they occur in the octahedral coordination polyhedron of the transition metal. In compound (III), no positional disorder in atomic sites is present. The Bi-O coordination polyhedra are trigonal prisms with one, two or three faces capped. Magnetic susceptibility data for compound (I) were obtained between 4.2 and 350 K. Between 4.2 and 250 K it is paramagnetic, μeff=6.1 μB; a magnetic transition occurs above 250 K. 相似文献
15.
张晨 《中国无机分析化学》2020,10(6):18-22
针对银精矿样品复杂,难消解的特点,研究了不同酸溶法和碱熔法对样品的消解情况,建立了硝酸,盐酸,氢氟酸,高氯酸消解银精矿的方法。根据元素灵敏度和抗干扰性,选定各元素的测定波长。通过酸溶样和碱熔样测定结果比对,验证了方法准确性。建立了四酸消解-电感耦合等离子体光谱法测定银精矿中铜、铅、锌、砷、镉、钙、镁、锰含量的方法,元素的线性相关系数均在0.9999以上。通过共存元素干扰实验,确定了银精矿中高含量元素(铜、铅、锌、铁、锑、铋等)对测定元素结果没有影响。方法检出限:Cu 0.0063 mg/L, Pb 0.0159 mg/L ,Zn 0.0090 mg/L,As 0.0192 mg/L, Cd 0.0093 mg/L ,Ca 0.0084 mg/L, Mg 0.0075 mg/L, Mn 0.0081 mg/L。测定下限:Cu 0.0105mg/L,Pb 0.0265 mg/L, Zn 0.0150 mg/L, As 0.0320 mg/L, Cd 0.0155 mg/L, Ca 0.0140 mg/L, Mg 0.0125 mg/L,Mn 0.0135 mg/L。3个样品的相对标准偏差在0.87%~3.56%之间,加标回收率在95.00%~103.56%之间。方法流程短,操作简单,快速,灵敏度和再现性高,结果准确可靠,可以满足银精矿中铜、铅、锌、砷、镉、钙、镁、锰含量的测定。 相似文献
16.
The room temperature structures of the five layer Aurivillius phases A2Bi4Ti5O18 (A=Ca, Sr, Ba and Pb) have been refined from powder neutron diffraction data using the Rietveld method. The structures consist of [Bi2O2]2+ layers interleaved with perovskite-like [A2Bi2Ti5O16]2− blocks. The structures were refined in the orthorhombic space group B2eb (SG. No. 41), Z=4, and the unit cell parameters of the oxides are a=5.4251(2), b=5.4034(1), c=48.486(1); a=5.4650(2), b=5.4625(3), c=48.852(1); a=5.4988(3), b=5.4980(4), c=50.352(1); a=5.4701(2), b=5.4577(2), c=49.643(1) for A=Ca, Sr, Ba and Pb, respectively. The structural features of the compounds were found similar to n=2-4 layers bismuth oxides. The strain caused by mismatch of cell parameter requirements for the [Bi2O2]2+ layers and perovskite-like [A2Bi2Ti5O16]2− blocks were relieved by tilting of the TiO6 octahedra. Variable temperature synchrotron X-ray studies for Ca and Pb compounds showed that the orthorhombic structure persisted up to 675 and 475 K, respectively. Raman spectra of the compounds are also presented. 相似文献
17.
TiO2,ZrO2-TiO2,andZrO2-TiO2-CeO2 were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), specific surface area measurements (BET), temperature programmed desorption (NH3-TPD), oxygen storage capacity (OSC), and temperature programmed reduction (H2-TPR). The results showed that ZrO2-TiO2-CeO2 exhibited large number of surface strong acid, possessed some oxygen storage capacity, and strong redox property. The three materials were used as supports and the monolith catalysts were prepared with 1% (w) V2O5 and 9% (w)WO3 for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive O2, and the results of catalytic activity showed that the catalyst used ZrO2-TiO2-CeO2 as support yielded nearly 100% NO conversion at 275 °C at a gas hourly space velocity (GHSV) of 10000 h−1, and it had the best catalytic activity and showed great potential for practical application. 相似文献
18.
通过调节B2O3-Bi2O3-ZnO-Al2O3(BBZA)玻璃的添加量研究其对钛酸钡(BaTiO3)陶瓷烧结条件、晶体结构和介电性能的影响。结果表明:添加适量的BBZA玻璃能够有效地将BaTiO3陶瓷烧结温度由1 350℃降至950℃,并使其致密化。同时,添加BBZA玻璃后,BaTiO3的晶体结构随着烧结温度的升高而发生转变(立方相→四方相)。另外,BBZA玻璃的引入使BaTiO3陶瓷的居里峰得到了有效的抑制和拓宽。陶瓷微观形貌显示,玻璃相均匀分布在BaTiO3晶粒表面。优化的BaTiO3陶瓷制备条件如下:BBZA添加量(质量分数)为2.0%,烧结温度为950℃。在该条件下制备的BaTiO3陶瓷介电常数达到1 364,介电损耗低至1.2%。 相似文献
19.
Noboru Kimizuka Francisco Brown Maria J. R. Flores Masaki Nakamura Yuichi Michiue Takahiko Mohri 《Journal of solid state chemistry》2000,150(2):276
The phase relations in the system In2O3–TiO2–MgO at 1100 and 1350°C are determined by a classical quenching method. In this system, there are four pseudobinary compounds, In2TiO5, MgTi2O5 (pseudobrookite type), MgTiO3 (ilmenite type), and Mg2TiO4 (spinel type) at 1100°C. At 1350°C, in addition to these compounds there exist a spinel-type solid solution Mg2−xIn2xTi1−xO4 (0≤x≤1) and a compound In6Ti6MgO22 with lattice constants a=5.9236(7) Å, b=3.3862(4) Å, c=6.3609(7) Å, β=108.15(1)°, and q=0.369, which is isostructural with the monoclinic In3Ti2FeO10 in the system In2O3–TiO2–MgO. The relation between the lattice constants of the spinel phase and the composition nearly satisfies Vegard's law. In6Ti6MgO22 extends a solid solution range to In20Ti17Mg3O67 with lattice constants of a=5.9230(5) Å, b=3.3823(3) Å, c=6.3698(6) Å, β=108.10(5)°, and q=0.360. The distributions of constituent cations in the solid solutions are discussed in terms of their ionic radius and site preference effect. 相似文献
20.
Wuzong Zhou 《Journal of solid state chemistry》2002,163(2):479-483
Microstructures of three Bi-W-Nb-O phases have been examined by using high-resolution transmission electron microscopy. Bi17W2Nb3O39 and Bi17WNb3O36 have incommensurate superstructures derived from the defect fluorite-type δ-Bi2O3 and can be regarded as intermediate phases between the type II solid solutions in the Bi-Nb-O and Bi-W-O systems. Bi8W2Nb2O23 has a Bi2WO6-like subunit cell with a stepped superstructure. Formation mechanisms of various superstructures are discussed. 相似文献