BiOCl纳米片微球的制备及其形成机理

以乙二醇为溶剂,采用溶剂热法制备了BiOCl纳米片微球.BiOCl纳米片交织在一起,形成开放的微孔结构.不同条件下合成的BiOCl形貌分析表明,纳米片微球的形成是乙二醇辅助生长的过程:乙二醇的2个氧原子与1个或2个铋离子配位生成含铋多聚络合物.在溶剂热过程中,Bi3+离子催化乙二醇聚合脱水,生成的水分子反过来原位促进金...     

Ｂｉ（ Ｎｂ） ＯＣｌ 光 催 化 剂 的 制 备 及 其 可 见 光 降 解罗 丹 明 Ｂ 溶 液 的 性 能

半导体光催化剂作为环境净化材料,具有稳定性好、光效率高、无二次污染等特点,具有广泛的应用前景.过去的研究大都集中在以TiO2为基础的光催化剂上.本文制备了具有层状结构的Bi基氧氯化物Bi(Nb)OCl光催化剂,用XRD、BET和UV-VIS吸收对样品进行了晶相、孔结构和光吸收性能表征,用罗丹明B的降解表征了材料的光催化活性.结果表明,BiOCl和Bi4NbO8Cl均具有可见光光催化降解活性,但两者的反应机理不同,Bi4NbO8Cl是光催化机制,BiOCl是染料光敏化机制.     

共模板法一步合成绣球状BiOCl/Br固溶体光催化剂

以乙二醇/十二烷基三甲基溴化铵(EG/DTAB)为共模板剂,一步制得BiOCl/Br的固溶体光催化剂,利用X射线衍射仪、扫描电子显微镜、能谱仪、N2吸附-脱附仪和紫外-可见漫反射光谱仪进行了表征.结果表明,与采用溶剂热法制得的BiOCl分级微球相比,采用EG/DTAB共模板法制得的BiOCl/Br固溶体具有更明显的分层结构,呈绣球状.同时,DTAB的Br-插入到BiOCl的晶格中,形成固溶体,减小了禁带宽度.绣球状BiOCl/Br固溶体具有比商用P25、二维BiOCl纳米片和三维BiOCl分级微球更优异的可见光间接敏化降解染料性能,当nDTAB/nKCl=0.75时,制得的BiOCl/Br固溶体8 min内在可见光下对罗丹明B(Rh B)的降解率达到97.2%;1 h后在可见光下对甲基橙(MO)的降解率达到83.6%.     

氯氧化铋催化剂的电子结构调控及其光催化性能研究

以不同Bi/Cl摩尔比例为原料设计合成了一系列BiOCl半导体催化材料。扫描电子显微镜、XRD衍射峰拟合等分析结果显示,Bi/Cl比例的改变对BiOCl的形貌、表面结构、微观电子结构均具有一定的调控作用。以Bi/Cl = 1 : 1为原料合成的BiOCl光催化剂具有最窄的带隙值（Eg=3.18 eV）,使得其具有较强的的光响应能力。光催化去除罗丹明B（RhB）结果表明,随着Bi/Cl摩尔比例的减小,BiOCl的催化性能呈现先增强后减弱的趋势。Bi/Cl = 1 : 1样品具有最优的催化活性,源于其较优异的光吸收性能以及特殊的表面特性。光催化机理研究表明,光催化去除RhB的过程中,起作用的活性物质主要为光生电子、空穴以及半导体表面产生的超氧自由基。     

Fe3O4纳米微球的溶剂热法合成及其对二甲酚橙的催化降解研究

以FeCl3·6H2O为单一铁源、1,2-丙二醇为还原剂和溶剂、尿素为均相沉淀剂、顺丁烯二酸为添加剂,通过简单一步溶剂热法于160℃制备出了形貌均一、单分散性好、尺寸约为200 nm的Fe3O4纳米微球。所制备的Fe3O4纳米微球不仅具有很高的磁化强度,而且在利用过氧化氢氧化降解二甲酚橙(XO)的过程中显示出很好的催化活性。紫外可见分光光度法考察表明,不加入Fe3O4催化剂时,1 h内双氧水对二甲酚橙的脱色率仅为6.2%,而加入Fe3O4纳米微球后,双氧水对二甲酚橙的脱色率在1 h内即可达到100%,循环使用10次后,Fe3O4纳米微球仍保持高的催化活性和结构稳定性。     

超声水热法制备高可见光催化活性的BiOCl-Bi12O17Cl2纳米复合材料去除染料和药物废水（英文）

光催化作为一种环境友好型、低能耗的技术,在环境净化等领域倍受关注.传统光催化剂,如TiO2,ZnO,V2O5和WO3等具有较高的光敏性,其价格低廉,自然无毒,常用于光电反应的应用当中.然而,这些催化剂具有较宽的禁带宽度,只能在紫外光下响应.为此,设计一种较窄带隙的高可见光活性的光催化剂具有一定的意义.近年来,氯氧化铋光催化剂受到了越来越多的关注,其在紫外光下具有非常优异的光催化性能.并且,研究者们已成功合成出非化学计量比的氯氧化铋,如Bi3O4Cl(2.60 eV),Bi12O17Cl2(2.10 eV),Bi12O15Cl6(2.86 eV)和Bi24O31Cl10(2.70 eV)等光催化剂.研究表明,较低的Cl/O比可能会减小催化剂的带隙宽度,并提高其光催化性能;其中Bi12O17Cl2的Cl/O比最小,是最有潜力的氯氧化铋光催化剂.然而,Bi12O17Cl2具有较高的光生电子空穴复合率,会极大的减弱其光催化活性.因此,将Bi12O17Cl2与具有高稳定性,结构相似且空穴复合率低的Bi OCl相结合,将会极大提高在可见光下Bi12O17Cl2的光催化活性.本文采用了超声水热法成功制备了具有高可见光催化活性的Bi OCl-Bi12O17Cl2纳米复合材料,用于去除染料和药物废水.扫描电子显微镜和比表面积分析仪的结果表明,纳米复合材料具有良好的分散性,结构为花瓣形状,其平均厚度为20至50 nm,且具有较高的比表面积.紫外-可见漫反射和光致发光光谱分析表明,纳米复合材料具有良好的可见光吸收性能,并且光生电子空穴复合率远低于Bi12O17Cl2.其在可见光下降解罗丹明B(/环丙沙星)的动力学常数分别约为Bi12O17Cl2,BiOCl和P25的8.14(/4.94),64.66(/11.91)和42.63(/36.07)倍.合适的形态,结构和光电性能是此纳米复合光催化剂具有优异光催化性能的原因.此外,该催化剂还显示出较宽的pH适用范围和优异的可重复利用性,有利于实际利用.机理研究表明,降解罗丹明B的主要活性物质是光生空穴和超氧自由基.总之,本文开发了一种绿色、稳定、高效的可见光光催化剂,对BiOCl基的光催化剂的研究作出了一定的贡献.     

铋掺杂二氧化钛纳米颗粒的制备及其可见光催化性能

采用水热法,以纳米管钛酸为前驱物制备了Bi掺杂的TiO₂,并利用X射线衍射、透射电子显微镜、X射线光电子能谱、紫外-可见漫反射光谱等手段对样品进行了表征. 以甲基橙的光催化降解为模型反应评价了样品的可见光催化性能. 结果表明,Bi离子并没有进入TiO₂的晶格中,而是以BiOCl的形式存在. 所制得的BiOCl/TiO₂复合物对甲基橙降解表现出较优越的可见光催化活性;当Bi/Ti摩尔比为1%,水热温度为130℃时,所制催化剂的光催化性能最佳,并对光催化活性提高的机理进行了讨论. 同时,该催化剂对4-氯苯酚降解也表现出较高的光催化性能.     

不同制备方法对BiOCl材料的形貌、结构与光催化性能的影响研究

对比采用溶剂热合成、传统固相合成与溶胶-凝胶合成技术,制备了四方相BiOC1和Nd3+掺杂BiOCl光催化材料.运用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)及紫外-可见吸收光谱(UV-Vis),研究了不同合成方法所制备BiOCl材料的相结构、形貌和紫外-可见光吸收性能;并以甲基橙溶液为模拟废水,研究了不同方法所制备的BiOCl材料的光催化性能.结果表明:溶剂热合成的BiOCl是由纳米片组装成粒径小于1μm微球,紫外-可见吸收边为335 nm;固相合成所得BiOCl结晶度较高,其片状颗粒粒径约为6μm,紫外-可见吸收边为430n m;溶胶-凝胶合成法制得BiOCl片状颗粒粒径约为3～4 μm,紫外-可见吸收边为430 nm.进一步地对比研究了稀土离子Nd3+掺杂前后BiOCl样品的结构、紫外-可见光吸收特性,可以发现,Nd3+掺杂后样品的相结构及形貌均无变化,但吸收边均发生不同程度的红移,以溶胶-凝胶法制得的样品效果最为明显,并具有最优的光催化性能.     

反应溶剂对Bi2S3粉体形貌的影响

利用溶剂热法在不同反应溶剂中制备了不同尺寸的Bi2S3纳米管和纳米棒.利用XRD、SEM、TEM、选区电子衍射(SAED)和高分辨透射电镜(HRTEM)对其结构和形貌进行了表征.结果表明,所制备的产物是结晶良好的正交相Bi2S3,反应溶剂的表面张力、粘度大小和反应溶剂中的比例影响纳米粉体的形貌和尺寸.紫外-可见光吸收光谱测量表明,由于尺寸效应所有粉体的吸收谱相对于正交相的Bi2S3块体都出现蓝移.     

异质结构AgCl/Bi_2WO_6微米球制备、表征及其光催化性能（英文）

首先利用水热法制备了由纳米片组装的粒径为1.5–2μm的Bi2WO6微球,然后在微球表面沉积了不同含量的AgC l(5 wt%,10 wt%,20 wt%,30 wt%),制备了异质结构Ag Cl/Bi2WO6微球光催化剂.利用X射线粉末衍射、扫描电镜、透射电镜、红外光谱、紫外-可见漫反射吸收等手段对所制的光催化剂进行表征,并以紫外光和可见光分别为光源,罗丹明B为降解对象测试了其光催化活性,考察复合不同含量的AgC l对Bi2WO6光催化剂的性能影响.结果表明,沉积AgC l对Bi2WO6的晶体结构、表面性能和光吸收性能没有产生明显影响,但大幅度提高了Bi2WO6的紫外和可见光催化活性.当复合20 wt%Ag Cl时,AgC l/Bi2WO6光催化活性最佳,紫外光下比纯Bi2WO6提高了2.2倍,可见光下提高了1倍.这主要是由于形成的Ag Cl/Bi2WO6异质结能有效抑制光生电子和空穴的复合,从而提了其光催化性能.     

PMDA-BPDA-HAB聚苯并噁唑的合成及耐热性

用廉价的均苯四甲酸二酐(PMDA)代替部分或全部3,3,′4,4′-联苯四羧酸二酐(BPDA),与3,3′-二羟基联苯胺(HAB)进行缩聚,然后脱水酰亚胺化,制备了5种聚酰亚胺(PI)。TGA分析显示,这些PI的DTG曲线为2个峰,可分为生成聚苯并唑(PBO)再发生PBO分解的2个阶段。PI膜在500℃通N2气1 h,所得聚合物膜的DTG曲线仅为1个峰,表明这些PI可充分转变成PBO。用FTIR表征了PI和PBO膜的结构。PBO的耐热性(用失重5%时的温度Td表示)比PI高100~170℃。PMDA-HAB PBO的耐热性高于BPDA-HABPBO。HAB-BPDA-PMDA PBO的耐热性优于二元PBO。当PMDA在二酐单体中所占的摩尔分数为75%时,PBO的Td高达643℃。     

Effect of Transition Metals on Selective Hydrogenation of Cinnamaldehyde over Pt／ZrO2 Catalysts

The effect of transition metals (Cr, Mn, Fe, Co and Ni) on the hydrogenation of cinnamaldehyde over Pt/ZrO2 catalysts was studied in ethanol at 343K under 2.0MPa H2 pressure. PtCo/ZrO2 and PtFe/ZrO2 catalysts exhibit high selectivity and activity of hydrogenation for C=O (93.8% at 87.3% conversion and 83.6% at 88.6% conversion, respectively), and PtNi/ZrO2 exhibits high selectivity of hydrogenation for C=C (64.3% at 70.6% conversion). In the presence of trace H2O and NaOH, over the PtNi/ZrO2 (0.4wt%Ni) catalyst the selectivity to hydrocinnamalde hydereaches 90.6% and the conversion of cinnamaldehyde is 90.5%.     

The development and application of guidance on equipment qualification of analytical instruments

 This paper describes the development of guidance for the equipment qualification (EQ) of analytical instruments. EQ is a formal process that provides documented evidence that an instrument is fit for its intended purpose and kept in a state of maintenance and calibration consistent with its use.     

Step-scan TMDSC and high rate DSC study of the multiple melting behavior of poly(1,3-propylene terephthalate)

The multiple melting behavior of poly(1,3-propylene terephthalate) (PPT) samples after isothermal crystallization from the melt was studied. The step-scan temperature-modulated differential scanning calorimetry (TMDSC) and high rate DSC were used to investigate this behavior in conjunction with standard DSC, wide-angle X-ray diffraction (WAXD) and polarizing light microscopy (PLM). The effect of PPT average molecular weight on the melting was also examined. In general multiple endotherms after isothermal crystallization of PPT were attributed to a continuous crystal perfection process during the subsequent heating scan via melting-recrystallization-remelting. Multiple melting behavior was more pronounced for the low molecular weight PPT. Step-scan TMDSC showed that extensive recrystallization occurs in PPT samples, especially after rapid isothermal crystallization. In fact two recrystallization exothermic peaks were observed. High rate DSC revealed the initial morphology generated during the isothermal step and showed that the low and middle peaks are associated with melting of primary crystals while the high temperature peak should be attributed to melting of recrystallized material.     

Synthesis and Multinuclear NMR Study of Benzoyl Methylene Triparatolylphosphorane Ylide and the Reaction of this Ylide with Mercury(II) Halides

The reaction of the title ylide {PhCOCHP(p-tolyl)₃} with Pd(II), Pt(II). Hg(II), and Ag(I) in equimolar ratios using CH₃CN, CH₃OH, and CH₂Cl₂ as solvents have yielded [{(p-tolyl)₃PCHCOC₆H₅} PdCl₂]₂ (I), [{(p-tolyl)₃ PCHCOC₆H₅} PtCl₂]₂(2), [Hg(NO₃)₂ {(p-tolyl)₃ PCHCOC₆H₅}](3), and [Ag{(p-tolyl)₃ PCHCOC₆H₅ < eqid1 > ₂]⁺ (4). The IR, ¹H ¹³C, and ³¹P NMR together with micro analysis data of the products were obtained.     

Biodegradations of block copolymers composed of L- or D,L-lactide and six-membered cyclic carbonates prepared with organolanthanide initiators

Diblock copolymerizations of L - or D,L -lactide (LA) with trimethylene carbonate (TMC) or 2,2-dimethyltrimethylene carbonate (2,2-DTMC) with SmMe(C₅Me₅)₂-(tetrahydrofuran) as an initiator and triblock copolymerizations of L - or D,L -LA/cyclic carbonates/L - or D,L -LA with [Sm(C₅Me₅)₂]₂(PhCCCCPh) as an initiator generated the desired block copolymers. This article describes the comparison of biodegradabilities by proteinase K and a compost and mechanical properties between the resulting di- or triblock copolymers and random copolymers composed of L - or D,L -LA and cyclic carbonates. The scanning electron microscopic profiles of resulting polymers were measured to understand the morphological change during biodegradation. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3572–3588, 2003     

Novel Designing of Chemically Modified Electrode (CME) of the Bio-MOF-1 for the Detection of Dopamine Based on Inhibition of [Ru(bpy)3]2+/DBAE System

Metal organic frameworks (MOFs) have attracted extensive attention in electrochemical research fields due to their high surface area and controlled porosity. Current study is design to investigate the ECL performance of the chemically modified electrode (CME) based on the bio-MOF-1, a porous zinc-adenine framework, which loaded ruthenium complex and employed for the detection of dopamine (DA). The composite material [Ru(bpy)₃]²⁺@bio-MOF-1 (Ru-bMOF) modified carbon glassy electrode (Ru-bMOF/GCE) exhibited an excellent ECL performance having a linear co-efficient response (R²=0.9968) for 2-(dibutyl amino) ethanol (DBAE), a classical ECL co-reactant was obtained over a concentration range of 1.0×10⁻⁹ M to 1.0×10⁻⁴ M in 0.10 M pH=6.0 phosphate buffer solution (PBS). Furthermore, DA was detected based on its inhibition effect on [Ru(bpy)₃]²⁺/DBAE system. Compared to traditional analytical methods, this method has various advantages such as simple electrode preparation, quick response, high reproducibility (RSD<2.0 %), low limit of detection (LOD=1.0×10⁻¹⁰ mol/L). This chemical investigated modified electrode had exploited potential for detection of DA.     

improvement of the Specificity of Surface Plasmon Resonance with BSA-modified Chip

Recently, surface plasmon resonance (SPR) become more and more popular without the need of the label technology1-3. However, sometimes, a number of experimental artifacts complicate the final biosensor analysis4-7. The utilization of a reference surface c…     

Determination of carcinoembryonic antigen using a novel amperometric enzyme-electrode based on layer-by-layer assembly of gold nanoparticles and thionine

Electrochemical sensing of carcinoembryonic antigen(CEA)on a gold electrode modified by the se- quential incorporation of the mediator,thionine(Thi),and gold nanoparticles(nano-Au),through co- valent linkage and electrostatic interactions onto a self-assembled monolayer configuration is de- scribed in this paper.The enzyme,horseradish peroxidase(HRP),was employed to block the possible remaining active sites of the nano-Au monolayer,avoid the non-specific adsorption,instead of bovine serum albumin(BSA),and amplify the response of the antigen-antibody reaction.Electrochemical ex- periments indicated highly efficient electron transfer by the imbedded Thi mediator and adsorbed nano-Au.The HRP kept its activity after immobilization,and the studied electrode showed sensitive response to CEA and high stability during a long period of storage.The working range for the system was 2.5 to 80.0 ng/mL with a detection limit of 0.90 ng/mL.The model membrane system in this work is a potential biosensor for mimicking the other immunosensor and enzyme sensor.