壳聚糖修饰掺硼金刚石薄膜电极测定铜离子

通过热丝化学气相沉积(HFCVD)的方法,以钽(Ta)为衬底,三氧化二硼(Be2O3)为硼源,制备掺硼金刚石(BDD)薄膜.并采用共价键合法进一步制得壳聚糖修饰BDD薄膜电极.以此修饰电极为工作电极,在0.1mol/L,pH=4的磷酸氢二钠缓冲液中对Cu2+进行检测.实验表明,Cu2+在4.0×10-7～1.0×10-...     

自组装时间和高温处理对Au/BDD电极表面形貌的影响及电化学性能分析

应用静电力自组装的方法在掺硼金刚石薄膜(BDD)电极表面制备了纳米Au颗粒的单层膜,通过高温加热使纳米Au颗粒牢固修饰在BDD薄膜表面。采用SEM和XPS对其表面形貌进行了表征,纳米Au颗粒在BDD薄膜表面分散均匀,且不存在团聚现象。采用循环伏安法和电化学阻抗谱对其电化学性能进行了研究,并对多巴胺进行了检测。结果表明:修饰后的BDD电极界面间电子转移速率显著提高,且对多巴胺表现出良好的电催化性;氧化峰电位由0.52V减小为0.3V,且氧化峰电流为BDD电极的1.9倍,检测限为3.0×10-6 mol/L,且在多巴胺和尿酸的混合溶液中有很强的选择性,为生物分子的检测提供了新方法。     

掺硼金刚石薄膜电极分析检测痕量镉、铅、铜、汞

采用热丝化学气相沉积方法(HFCVD)制备硼掺杂金刚石(BDD)薄膜电极,并对BDD电极进行了表征和活化处理。以制备的BDD电极为工作电极利用阳极溶出伏安法对镉、铅、铜、汞重金属离子进行检测分析,考察了扫描方式、工作电极、支持电解液、p H值、电极硼掺杂浓度、富集时间、富集电位等因素对检测的影响。在优化实验条件下,对1-7 ppb的镉、铅、铜、汞重金属离子进行了同时检测,结果表明BDD电极对镉、铅、铜、汞重金属离子溶出峰的分离度较好,具有良好的线性度和重复性。     

硼掺杂金刚石薄膜电极的制备及电化学行为研究

硼掺杂金刚石薄膜(BDD)电极具有良好的电化学性能,是一种理想的电极材料。采用扫描电子显微镜、X射线衍射、拉曼光谱对制得的BDD电极的结构进行了表征。电极表面薄膜生长致密,晶体生长取向以(111)晶面为主,生长速率为2.8μm/h,晶格常数为3.5738。利用循环伏安法(CV)研究了BDD电极在铁氰化钾/亚铁氰化钾体系中氧化还原反应的可逆性和动力学特征。研究结果表明,在铁氰化钾/亚铁氰化钾的浓度为20mmol/L条件下,BDD电极的氧化还原峰电势差达到205.75mV,在溶液中电极的氧化还原反应属于准可逆反应,氧化峰电流与反应物浓度成正比,电极过程动力学是受扩散控制为主。     

纳米金颗粒修饰的掺硼金刚石薄膜电极对三价砷离子的定量检测

采用静电力诱导自组装的方法将纳米金颗粒自组装到掺硼金刚石薄膜(BDD)电极表面,采用扫描电子显微镜和X射线光电能谱仪对其表面进行表征。对自组装在BDD电极表面的纳米金颗粒进行种子生长,并用于检测BDD电极之前无法检测的As~(3+)。采用溶出伏安法分别研究了富集时间、富集电位以及电解质溶液对As~(3+)检测的影响,选择出合适的检测参数完成对As~(3+)的定量检测。在盐酸为电解质的条件下,As~(3+)的浓度在小于3×10-6g/L时,As~(3+)的浓度与氧化峰电流表现出良好的线性关系,且最低检测限为0.3×10-6g/L。     

纳米金颗粒在掺硼金刚石薄膜电极表面的自组装及其电化学性能分析

对阳极氧化后的掺硼金刚石(BDD)薄膜进行表面氨基化处理,使柠檬酸根包裹的纳米金颗粒(粒径约18nm)自组装到BDD薄膜的表面。通过改变纳米金溶液的pH值,在BDD薄膜表面制备出二维形貌分布均匀且相对覆盖度高(约30%)的纳米金颗粒。在[Fe(CN)6]3-/4-体系中,通过循环伏安分析和交流阻抗分析实验发现,纳米金颗粒修饰后的BDD电极表面异相电子转移速率常数(Kapp)由2.8×10-4提高到8.9×10-4。纳米金颗粒修饰的BDD电极对多巴胺的氧化电位由0.54V减小到0.3V,且氧化峰峰值得到提高,证实了纳米金颗粒对多巴胺的催化作用。     

水热电化学法制备LiCoO2薄膜和粉末

采用水热电化学法同时制备出LiCoO2粉末和薄膜.LiCoO2粉末是由菊花状晶粒组成,LiCoO2薄膜由0.2～0.4μm左右的颗粒堆积而成.LiCoO2薄膜电极首次循环伏安过程在3.85V和4.3V左右出现强氧化峰,在3.6V左右出现还原峰;LiCoO2粉末的首次循环伏安过程在4.3V左右出现强氧化峰,在3.5V左右出现还原峰;在随后的循环中,氧化和还原峰对应的电位和强度衰减程度小,表明该方法制备的LiCoO2正极材料具有良好的循环伏安性能.     

热丝化学气相沉积制备BDD薄膜电极的电催化特性

研究了热丝化学气相沉积法(HFCVD)制备得到掺硼金刚石膜电极电催化氧化典型有机物苯酚的特性.Raman光谱测试显示制备BDD电极具有较好的金刚石相,循环伏安测试表明该电极具有较高的析氧过电位(+2.3V vsSCE).在电催化氧化苯酚过程中,化学需氧量(COD)能够有效去除,降解过程中有较高的电流效率,在COD较高的情况下,瞬时电流效率(ICE)可达100%,随着COD的降低ICE逐渐减少.催化实验结果表明,BDD电极是一种优良的电催化降解有机物新型电极.     

石墨粉末化学镀Ni-P催化剂表面乙醇的电催化氧化

电催化乙醇氧化的阳极材料易失效.在活性炭(C活性)上化学沉积Ni-P颗粒,制备了Ni-P/C活性催化剂,将其填入213型铂电极凹槽之中,制成Ni-P/C活性电极.采用扫描电镜(SEM)和电化学循环伏安法对Ni-P/C活性催化剂性能进行了研究.结果表明:球状Ni-P颗粒以约为100 nm的大小均匀分布于C活性表面;仅C活性电极能催化乙醇发生氧化,但易失活,而Ni-P/C活性电极可以催化乙醇在-0.24 V发生氧化,在阴极极化扫描过程中,-0.39 V时会出现乙醇氧化中间物的氧化峰,催化乙醇氧化的峰电流随循环使用次数的增加而提高,氧化电位逐渐负移,这与Ni-P在碱性条件下电氧化产生Ni(OH)2和NiOOH有关.     

叶酸在聚苯胺修饰铂电极上的电催化氧化行为

采用电化学聚合法制备了聚苯胺修饰的铂电极(PAN/Pt),并用循环伏安法(CV)研究了该电极对叶酸(FA)的电催化氧化性能。结果显示:FA在裸铂电极上的直接电化学氧化十分迟缓,无氧化峰出现,而在PAN/Pt修饰电极上0.561V处出现氧化峰,表明此电极对FA有很良好的电催化作用。另外,氧化峰电流与叶酸浓度在1×10-12 mol/L~1×10-6 mol/L范围内呈线性关系,检测限为1×10-11 mol/L。利用该电极测定市售叶酸片中的叶酸,获得令人满意的结果。     

Sputter deposition of bcc tantalum films with TaN underlayers for protection of steel

Deposition of tantalum films for protective coatings on steel has been investigated. The desired tough and ductile bcc phase of tantalum, rather than the normally deposited hard and brittle tetragonal phase, has been grown by DC magnetron sputtering on unheated substrates first covered with thin layers of tantalum nitride. The nitride was formed by reactive sputtering with nitrogen gas, with the same DC magnetron source and target as used for deposition of tantalum. The crystal structure and composition of the nitride promoting the growth of bcc Ta, previously undefined, has been identified as the metastable fcc (NaCl like) TaN. Alignment of the (111) crystallographic planes of fcc TaN with (110) planes of bcc Ta is discussed as a possible mechanism for this effect. The minimum thickness of TaN underlayer on steel, required to promote the growth of bcc Ta, has been established and found to be dependent on the substrate surface preparation. Scratch tests with a diamond tip showed that the nitride underlayer does not compromise the film adhesion. Stable and well-adhering coatings of bcc Ta with thickness ranging from tens of nanometers to tens of micrometers on steel with a thin TaN underlayer were obtained. The process of deposition of bcc Ta films, including the formation of TaN underlayers is described in detail.     

Applicability of boron-doped diamond electrode to the degradation of chloride-mediated and chloride-free wastewaters

The electrochemical degradation of chloride-mediated and chloride-free dye wastewaters was investigated on a boron-doped diamond (BDD) electrode in comparison with that on a dimensionally stable anode (DSA), and the applicability of BDD electrode to the degradation of these two kinds of wastewaters was explored. In chloride-free wastewater, the electrochemical degradation efficiency of dye on BDD electrode was much higher than that on DSA, with a chemical oxygen demand (COD) removal of 100% and 26% for BDD and DSA, respectively. In chloride-mediated dye wastewater, COD removal was faster than that in chloride-free wastewater on both BDD and DSA electrodes with COD removal efficiencies higher than 95%, whereas the rate of COD removal on DSA was faster than that on BDD electrode. The investigation indicates that DSA is more suitable than BDD electrode in degradation of originally chloride contained dye wastewaters for the sake of energy and time saving. However, for chloride-free dye wastewaters, with the aim of environmental protection, BDD electrode is more appropriate to realize complete mineralization. At the same time, the secondary pollution can be avoided.     

Electrochemical degradation of chlorobenzene on boron-doped diamond and platinum electrodes

In this paper the electrochemical degradation of chlorobenzene (CB) was investigated on boron-doped diamond (BDD) and platinum (Pt) anodes, and the degradation kinetics on these two electrodes was compared. Compared with the total mineralization with a total organic carbon (TOC) removal of 85.2% in 6 h on Pt electrode, the TOC removal reached 94.3% on BDD electrode under the same operate condition. Accordingly, the mineralization current efficiency (MCE) during the mineralization on BDD electrode was higher than that on the Pt electrode. Besides TOC, the conversion of CB, the productions and decay of intermediates were also monitored. Kinetic study indicated that the decay of CB on BDD and Pt electrodes were both pseudo-first-order reactions, and the reaction rate constant (k_s) on BDD electrode was higher than that on Pt electrode. The different reaction mechanisms on the two electrodes were investigated by the variation of intermediates concentrations. Two different reaction pathways for the degradation of CB on BDD electrode and Pt electrode involving all these intermediates were proposed.     

掺硼金刚石薄膜的电化学性能

利用循环伏安法,通过对比掺硼金刚石薄膜电极和铂／金刚石电极分别作为工作电极时的循环伏安曲线,分析了两种电极表现出的电化学性能差别,并利用能级理论进行了机理探讨。结果表明掺硼金刚石薄膜电极具有宽的电化学窗口（宽度约为3V）、良好的化学稳定性和极低的背景电流（接近0）,是一种较有潜力的电化学电极材料。     

Ti/BDD电极和Ti/IrO_2-RuO_2电极降解苯酚的对比研究

研究了两种以Ti为基体,气相法沉积硼掺杂金刚石薄膜(BDD)电极和热分解方法着附IrO2-RuO2涂层电极对工业难降解污染物——苯酚的降解能力。采用循环伏安法,探讨了两种电极的电化学性能。结果表明,以亚甲基蓝作为氧化物的捕获剂,在相同的实验条件下,DSA电极产生氧化物(ClO-)的速度大于BDD电极产生等量氧化物(·OH)的速度。用两种Ti基电极分别降解苯酚溶液48h,BDD电极对苯酚的降解率几乎达到100%,而IrO2-RuO2涂层电极仅为35.6%。苯酚溶液的COD去除率在IrO2-RuO2涂层电极下仅为27.8%,在BDD电极下达到95.3%,且反应产物不易积累。因此,Ti基BDD电极在含芳香类化合物的污水处理方面有较高的应用价值和广阔的推广前景。     

Microchip capillary electrophoresis coupled with a boron-doped diamond electrode-based electrochemical detector

The attractive behavior and advantages of a diamond electrode detector for a micromachined capillary electrophoresis (CE) system are discussed. A chemically vapor-deposited boron-doped diamond (BDD) film band (0.3 x 6.0 mm) electrode is used for end-column amperomettic detection. The favorable performance of the diamond electrode microchip detector is indicated from comparison to a commonly used thick-film carbon detector. The diamond electrode offers enhanced sensitivity, lower noise levels, and sharper peaks for several groups of important anaytes (nitroaromatic explosives, organophosphate nerve agents, phenols). The favorable signal-to-background characteristics of the BDD-based CE detector are coupled with a greatly improved resistance to surface fouling and greater isolation from high separation voltages. The enhanced stability is indicated from a RSD of 0.8% for 60 repetitive measurements of 5 ppm 2,4,6-trinitrotoluene (vs RSD of 10.8% at the thick-film carbon electrode). A highly linear response is obtained for the explosives 1,3-dinitrobenzene and 2,4-dinitrotoluene over the 200-1,400 ppb range, with detection limits of 70 and 110 ppb, respectively. Factors influencing the performance of the BDD detector are assessed and optimized. The attractive properties of BDD make it very promising material for electrochemical detection in CE microchip systems and other micromachined flow analyzers.     

Fabrication of boron-doped diamond ultramicroelectrodes for use in scanning electrochemical microscopy experiments

Boron-doped diamond (BDD) ultramicroelectrode (UME) tips were fabricated by the growth of BDD films by chemical vapor deposition onto sharpened tungsten wires. Both nanocrystalline and microcrystalline forms of diamond coatings were examined. The diamond-coated wires were selectively insulated with nail varnish, electrophoretic paint, or fast-setting epoxy to form UME tips of critical dimensions of 1-25 microm. The geometry of the exposed electrode area was disk or hemispherical in most cases. Cyclic voltammetry and chronoamperometry were used to assess exposed electrode area and integrity of the insulation. BDD UMEs were used to obtain SECM approach curves to an insulating and a conducting substrate, which were fitted to the theory appropriate for the observed tip geometry. The tips were used to obtain SECM images of immobilized respiring E. coli, illustrating the suitability of BDD UMEs for electrochemical imaging in biological media.     

气压和偏流对高掺硼金刚石晶体性质的影响(英文)

采用热丝化学气相沉积法,改变工作气压和偏流,在硅基片上沉积了高掺硼金刚石膜。利用扫描电镜(SEM)、拉曼光谱和X射线衍射仪对沉积的金刚石膜表面形貌和结构进行表征。结果显示:当气体压强从3kPa降低到1.5kPa时,金刚石膜有较平的表面形貌和和较好的晶形,薄膜的晶体性质得到良好的改善。但是继续降气体压强,从1.5kPa到0.5kPa时,却呈现出相反的趋势。固定气体压强(1.5kPa),改变偏流,结果表明:适当的偏流(3A)可以改善掺硼金刚石的质量,偏流较高会导致薄膜中非金刚石相增多。     

热处理对MIM薄膜二极管Ta2O5绝缘膜微结构及其I-U特性的影响

制备了一种用于有源矩阵液晶显示、具有对称结构的MIM薄膜二极管 ,其中Ta2 O5膜采用溅射 /阳极氧化两步法工艺制成。对绝缘膜进行真空热处理 (一步热处理 )和经真空热处理后再进行大气热处理 (真空 /大气两步热处理 )。用原子力显微镜和透射电子显微镜分析了Ta2 O5膜的微结构 ,测试了MIM薄膜二极管的I U特性曲线。讨论了热处理对Ta2 O5绝缘膜微结构和MIM薄膜二极管I U特性的影响 ,并指出了MIM薄膜二极管I U特性和绝缘膜微结构之间的关系