多晶n-CdSe电极在K_4Fe(CN)_6-EDTA溶液中稳定性的研究

旋转环盘电极(RRDE)研究表明,多晶n-CdSe电极表面经金属离子溶液处理,提高溶液的pH及增加溶液中还原剂K_4Fe(CN)_6的浓度均使该电极在K_4Fe(CN)_6-FDTA体系中的稳定因子S提高。用Au、Ru、Pt及Pb等离子溶液处理电极表面时,S值增大。Ru离子处理使S增大几乎可达1。从X射线荧光光谱和Mott-Schottky关系图分析证明,处理后的CdSe多晶电极表面沉积了一层金属薄层。本文对电极表面沉积的金属薄层、溶液pH等的影响、稳定因子S提高的原因也作了初步讨论。     

纳米TiO2膜电极光电催化降解污染物的研究进展

纳米TiO2基薄膜光电催化通过外加偏压阻止光生电子与空穴发生复合以提高光催化的量子效率,并使有机污染物发生深度矿化。本文详细介绍了光电催化的反应机理、TiO2基薄膜电极的制备及提高光电催化效率的主要途径、影响光电催化过程的主要因素等,最后对TiO2光电催化的发展方向进行了展望。     

二氧化钛薄膜光电催化Cr(Ⅵ)的影响因素

以TiO2薄膜为工作电极,铂网作为辅助电极,甘汞电极为参比电极,进行紫外光光电催化还原Cr(VI),探讨了溶液初始pH值、Cr(VI)初始浓度以及柠檬酸浓度对反应性能的影响。结果表明,在酸性条件下,TiO2对Cr6+离子污染具有显著的光电催化还原消除效果;随着Cr(VI)初始浓度的增加,其光电催化还原反应速率降低;柠檬酸作为空穴捕获剂可有效地捕获光生空穴,在一定浓度范围内,Cr(VI)的光电还原反应速率随柠檬酸浓度的增加而增加。在pH为3、0.6 V偏压、0.006 g柠檬酸条件下,初始浓度为10 mg/L的Cr(VI)反应210 min时,其转化率达到82.19%。     

N-Mn-TiO2/AC粒子电极的制备及其降解性能研究

以传统活性炭(AC)粒子电极为载体，采用溶胶-凝胶法制备TiO₂/AC粒子电极以及掺N、掺Mn、N-Mn共掺杂改性的TiO₂/AC粒子电极，并将几种粒子电极应用于三维光电系统，考察其对实际印染废水的处理性能。XRD表征结果表明，TiO₂成功负载于AC表面且以锐钛矿晶型为主，N元素并未取代晶格氧，而是进入TiO₂晶格间隙，加快了电荷转移，Mn元素则以间隙掺杂形式进入TiO₂晶格，加快了光生空穴(h+)的转移；SEM、EDS和FT-IR结果显示，相比TiO₂/AC粒子电极，N-Mn-TiO₂/AC粒子电极比表面积显著增大，含氧官能团明显增加；印染废水降解实验结果表明，当实际印染废水中COD、NH₄⁺-N、TN分别为1 600～1 800、25～40、40～60 mg/L时，N-Mn-TiO₂/AC三维光电体系对COD、NH₄⁺-N...     

Ag-Ti3+-TiO2纳米锥的制备及光电催化性能研究

抗生素的过度使用对环境造成了持久性的污染,光电催化是降解抗生素的环保、高效技术,其中光电极的设计尤为重要。为提高抗生素降解速率,采用电化学还原和光还原法制备了Ag-Ti³⁺-TiO₂纳米锥复合光电极,并用于模拟可见光照射下光电催化降解四环素的过程,考察其光电催化性能。结果表明,由于Ti³⁺自掺杂和Ag纳米颗粒的局域表面等离子体共振效应,复合电极有效地抑制了光生电子-空穴对的复合,并表现出更低的电荷转移电阻,提高了光电催化性能。复合光电极在可见光照射下,90 min后可降解87.9%的四环素,且5个循环后降解率保持在82.5%。这些结果表明,Ag-Ti³⁺-TiO₂纳米锥复合光电极具有高降解效率、良好的稳定性和可持续的循环利用性,有望实现高效环保地光电催化降解抗生素。     

Ni(OH)2修饰对a-Fe2O3薄膜光电化学性能的增强效应

利用一种简便的电沉积方法制备氧化铁薄膜,并在过程中引入Ni(OH)₂进行修饰,对具体电沉积实验参数进行优化,从而建立最佳制备条件。利用场发射扫描电子显微镜、X射线粉末衍射对Fe₂O₃/Ni(OH)₂光电极膜的结构进行表征。利用循环伏安和计时电流测量析氧过电位和光电流密度。结果表明,Ni(OH)₂修饰的α-Fe₂O₃薄膜可提高光生电子与空穴的分离效率,从而显著提高光电催化活性。     

二氧化钛平推流反应器光催化矿化草甘膦研究

在平推流光化学反应器中采用纳米TiO2光催化矿化N-(膦酰基甲基)甘氨酸(草甘膦)溶液,考察了多种因素对矿化效果的影响。结果表明,在碱性溶液中,OH-可以充当光致空穴的俘获剂,从而提高了草甘膦的光催化矿化效率;外加氧化剂可以作为电子的接受体,通过接受光生电子来抑制光生电子与光生空穴的复合,提高光催化反应的量子产率,从而促进草甘膦的光催化矿化;升高温度可促进具有强氧化性自由基的生成,同时也可抑制光生电子和光生空穴的复合,促进草甘膦在催化剂表面的矿化;外加有机物可与草甘膦共同竞争催化剂表面的活性位点,从而阻碍了草甘膦在催化剂表面的矿化;在一定范围内,光催化矿化率随无机离子浓度的增加而升高,但当无机离子的质量浓度>4 mg/L时,矿化率下降。     

Ru(bpy)2(NCS)2染料敏化PbS/Zn2+--TiO2复合半导体纳米多孔膜电极的光电化学

采用水热法合成了Zn2+离子掺杂的TiO2纳米粒子(掺杂量0.5%),并用光电化学方法研究了Ru(bpy)2(NCS)2(bpy=2,2'-bipydine-4,4'-dicarboxylicacid)分别敏化Zn2+掺杂的TiO2电极和PbS/Zn2+-TiO2复合半导体纳米多孔膜电极的光电化学行为.实验证明Ru(bpy)2(NCS)2敏化PbS/Zn2+-TiO2复合半导体纳米多孔膜电极比单独敏化Zn2+-TiO2电极的光电效果好,且敏化电极的光电流产生的起始波长都比Zn2+-TiO2电极向长波方向移动;在360600nm范围内,Ru(bpy)2(NCS)2敏化PbS/Zn2+-TiO2复合半导体纳米多孔膜电极比单独敏化Zn2+掺杂TiO2电极的效果更好.     

Ti-2Al-1.5Mn合金表面纳米管阵列薄膜的光电化学响应特性研究

采用阳极氧化法在20V条件下氧化3h于TC1(Ti-2Al-1.5Mn)合金表面制备了纳米管阵列薄膜。研究了薄膜的表面形貌及结构,着重考察其作为光电极的开路电位和光生电流响应特性。结果表明,该纳米管膜具有高度有序的纳米管阵列结构,平均管径90nm,管长520nm。经过600℃热处理后,该薄膜电极光电响应速度快,光生电子和空穴的复合少,电子的传输效率高。     

4-(2-吡啶偶氮)间苯二酚的库仑滴定

4-(2-吡啶偶氮)间苯二酚简称PAR。在通常情况下,用还原剂Cr~(2+)、Ti~(3+)滴定,还原过程较慢。本文提出在室温下,在0.02MBritton-Robinson-0.2M柠檬酸钠-0.1MTiCl_4酸性溶液中(pH2)用电生Ti~(3+)库仑滴定PAR。Ag-Hg电极为工作电极,铂电极为辅助电极,两极用陶瓷膜隔开,用电流法指示终点。     

(S)-(+)-5-羟甲基-2-吡咯烷酮的合成方法改进

通过实验证明在(S)-( )-5-羟甲基-2-吡咯烷酮合成中，以硼氢化钠为还原剂时，所得产品产率和纯度都有大幅度提高；且实验操作简单方便，适合工业化。     

Catalytic glucose oxidation on a polycrystalline gold electrode with an amalgamation treatment (TM 05092)

Different behaviors in the glucose electrooxidations on polycrystalline gold electrodes, after various treatments including annealing, alumina polishing, and amalgamation, were compared. On a gold electrode after the amalgamation treatment, in comparison to the commonly used alumina polished electrode, a catalytic effect was observed. Two oxidation waves at 0.0 and 0.3 V (versus Ag|AgCl) were observed while only one wave at 0.3 V was shown on the latter electrode. Large current enhancement was also observed. The relationship of the current at 0.3 V versus the microscopic surface area showed a positive deviation from the linearity indicating the enhanced exposure of surface active sites for the glucose oxidation. The appearance of the new oxidation wave at 0.0 V implies the introduction of active sites of different surface structure on the electrode surface. We now suggest that the exposed active surface sites may be related to the low index single crystal structures based on their reported similar responses in the glucose oxidation. In the presence of Cl⁻ ions in the solution, the prominent inhibition effect was observed. The amalgamation treatment gave the effects of reducing the overpotential and increasing the currents for the glucose oxidation.     

Control of NOx Emissions from Diesel Engine by Selective Catalytic Reduction (SCR) with Urea

Among the catalysts screened, Cu-ion exchanged ZSM5 zeolite exhibited the highest NO removal activity, particularly at low reaction temperatures below 200 °C, maintaining a wide operating temperature window. The hydrothermal stability of the CuZSM5 catalyst can be improved by the optimization of metal content of the catalyst. Through the variation of reactor operating conditions, NO conversion of better than 90% could be achieved with a minimum NH₃ slip. The decomposition of urea was also examined and a kinetic model for both thermal and catalytic decomposition of urea was developed. Urea-SCR over the CuZSM5 catalyst exhibited that the NO removal activity is competitive to that by NH₃-SCR, indicating urea can be effectively utilized in SCR reactor system as the reducing agent.     

Cr(III) oxidation with lead dioxide-based anodes

A procedure for preparing PbO₂-based electrodes with a titanium substrate is proposed. A platinum underlayer is first deposited on Ti by metal organic chemical vapor deposition (MOCVD), followed by the electrodeposition of the PbO₂ layer. The prepared Ti/Pt/PbO₂ anodes were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD) before being used for oxidation of Cr(III) in sulphuric acid. The current efficiency was determined for that electrodes and the results were compared with those obtained with Pb/PbO₂ and Ebonex^®/PbO₂ electrodes with different pH conditions. The Ti/Pt/PbO₂ were found to have a very good electrochemical behaviour (current efficiency: φ=0.93 for pH 2), and may be used as dimensionally stable anodes for the oxidation of Cr(III).     

4-溴乙基-5-氟嘧啶的合成

伏立康唑是由美国辉瑞公司研究开发的第二代三唑类抗真菌药物,具有抗菌谱广,抗菌效力强的特点。4-溴乙基-5-氟嘧啶是合成伏立康唑的重要中间体,在对文献中几条工艺路线分析比较的基础上,优化出一条较为理想的合成工艺路线,该路线以5-氟尿嘧啶为起始原料,经三氯氧磷氯化,与溴化乙基镁通过格氏反应乙基化,经高锰酸钾氧化后进行氢解脱氯,再经N-溴代琥珀酰亚胺溴化制得4-溴乙基-5-氟嘧啶。总收率为45.8%。     

Effects of synthetic route on structure and electrochemical performance of Li3V2(PO4)3/C cathode materials

Three different synthetic routes, including solid-state reaction, sol–gel and hydrothermal methods are successfully used for preparation of Li₃V₂(PO₄)₃/C. Ascorbic acid is used as a reducing agent and/or as a chelating agent. The Li₃V₂(PO₄)₃/C synthesized by hydrothermal method with fine particles exhibits lower impedance and smaller potential difference values between oxidation and reduction peaks than those by solid-state reaction and sol–gel methods. Thus as cathode material for Li-ion batteries, the Li₃V₂(PO₄)₃/C synthesized by hydrothermal method shows higher discharge capacity, better rate capability and cyclic performance. Even at a high charge–discharge rate of 10 C, it still can deliver a discharge capacity of 101.4 mAh g⁻¹ and 106.6 mAh g⁻¹ in the potential range of 3.0–4.3 V and 3.0–4.8 V, respectively. The hydrothermal synthesis has been considered to be a competitive process to prepare Li₃V₂(PO₄)₃/C cathode materials with excellent electrochemical performances.     

新型钛基体PbO2电极的制备及降解性能研究

采用电沉积法制备钛基体PbO2电极并对其表面形貌进行了表征,所制备的电极具有较高的析氧电位和良好的电催化活性。以制备的钛基PbO2为阳极,抛光钛电极为阴极,分别进行电流密度、反应时间、pH、电解质质量浓度等单因素试验,确定PbO2电极对亚甲基蓝的最优降解条件为:pH=6,电解质质量浓度为5.0 g.L-1,电流密度为5×10-2A.cm-2,该条件下亚甲基蓝1 h的降解率可以达到99%;且电流密度为0.25×10-2A.cm-2时能耗最低。     

SHS为链转移剂合成低分子量聚丙烯酸钠及其共聚物

以水为溶剂，APS－SHS氧化还原引发体系，研究了丙烯酸及其共聚物的合成。结果发现，SHS既是还原剂，又是链转移剂，其用量＞3％时可得到分子量＜2万，且无色或淡黄色透明的低分子量聚合物。     

稀土偶联剂（REC）对PP／Mg（OH）2体系性能的影响

研究了稀土偶联剂（ＲＥＣ）处理对ＰＰ／氢氧化镁（Ｍｇ（ＯＨ）２）体系的燃烧性能、流动性能、力学性能及老化性能的影响。未经处理的Ｍｇ（ＯＨ）２在填充量超过５０％时,ＰＰ／Ｍｇ（ＯＨ）２体系的ＯＩ≥２８．５,但这时冲击强度不足纯ＰＰ的３０％,熔体流动速率低于０．６ｇ／１０ｍｉｎ;而填料用２．５％（重量）ＲＥＣ处理后,填充量为５０％的体系冲击强度接近纯ＰＰ,ＭＦＲ达２．８ｇ／１０ｍｉｎ;ＲＥＣ对Ｍｇ（Ｏ     

The ultrasonic electropolymerization of an 5-[o-(4-bromine amyloxy)phenyl]-10,15,20-triphenylporphrin (o-BrPETPP) film electrode and its electrocatalytic properties to dopamine oxidation in aqueous solution

5-[o-(4-Bromine amyloxy)phenyl]-10,15,20-triphenylporphrin (o-BrPETPP) was electropolymerized on a glassy carbon electrode (GCE), and the electrocatalytic properties of the prepared film electrode response to dopamine (DA) oxidation were investigated. A stable o-BrPETPP film was formed on the GCE under ultrasonic irradiation through a potentiodynamic process in 0.1 M H₂SO₄ between −1.1 V and 2.2 V versus a saturated calomel electrode (SCE) at a scan rate of 0.1 V s⁻¹. The film electrode showed high selectivity for DA in the presence of ascorbic acid (AA) and uric acid (UA), and a 6-fold greater sensitivity to DA than that of the bare GCE. In the 0.05 mol L⁻¹ phosphate buffer (pH 6.0), there was a linear relationship between the oxidation current and the concentration of DA solution in the range of 5 × 10⁻⁷ mol L⁻¹ to 3 × 10⁻⁵ mol L⁻¹. The electrode had a detection limit of 6.0 × 10⁻⁸ mol L⁻¹(S/N = 3) when the differential pulse voltammetric (DPV) method was used. In addition, the charge transfer rate constant k = 0.0703 cm s⁻¹, the transfer coefficient α = 0.709, the electron number involved in the rate determining step n_α = 0.952, and the diffusion coefficient D_o = 3.54  10⁻⁵ cm² s⁻¹ were determined. The o-BrPETPP film electrode provides high stability, sensitivity, and selectivity for DA oxidation.