电活性分子L-B膜修饰CdSe薄膜电极的光电化学研究

用电活性分子——硬脂酸二茂铁酯L-B膜修饰了薄膜CdSe电极,在单色光650nm光照下用循环伏安法研究修饰的薄膜电极的光电化学性能。研究结果指出经多层L-B膜修饰后,薄膜CdSe电极的,I-V性能和光稳定性都有明显改善。用界面能级关系讨论了硬脂酸二茂铁酯L-B膜在光照的CdSe薄膜/Fe(CN)_6~(4-)溶液界面起传递电荷的中介作用,加速了界面的电荷转移。     

修饰的薄膜CdSe电极／Fe（CN）6^4—溶液界面的电荷转移

本文研究了硬脂酸二茂铁酯L-B膜修饰的薄膜Cdse电极的光诱发界面多相电荷转移过程。通过测量异相电荷转移反应速度常数K_(et),进一步分析了修饰的薄膜CdSe电极光电化学过程的可能反应速度控制步。分析表明界面的电荷转移是反应的速度控制步。薄膜CdSe电极可以通过选择电活性修饰分子和溶液中氧化还原离子来进一步提高和改善其光电化学性能。     

薄膜CdSe及CdSexTe1—x电极的光电子能谱研究

用X射线光电子能谱(XPS)研究了不同含氧气氛中烧结的薄膜CdSe及Cdse_xTe_(1-x)电极表面,以及薄膜与Ti底基之间的界面。研究中发现,二种薄膜电极的表面形成了CdO,SeO_2及TeO_2氧化物,与薄膜接触的Ti底基表面上形成了TiO_2。用俄歇电子能谱(AES)对在电极表面及Ti表面所生成的氧化层分别进行了深度分析。结果表明,各种氧化物形成的程度有很大的不同,氧化层厚度也存在差异。对影响薄膜电极的光电性能的因素进行了讨论。     

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。     

不同基材上Co掺杂CdSe薄膜电极的制备及光电催化性能

采用脉冲电流沉积法制备了负载于氧化锡铟(ITO)导电玻璃、不锈钢板、镍板和铜板等不同基材上的Co掺杂CdSe薄膜电极,利用紫外可见漫反射和交流阻抗实验测试了Co掺杂CdSe薄膜电极的性能,并以对硝基苯酚降解来评价该薄膜的光电催化性能.结果表明:基材的种类对Co掺杂CdSe薄膜电极的性能影响较大,其催化降解对硝基苯酚的活...     

L-半胱氨酸在金电极上的自组装及其电化学性能研究

将L-半胱氨酸(L-Cys)自组装到金电极表面制成L-Cys/Au修饰电极,并用电化学方法研究了它的电化学性质。研究了葡萄糖在自组装膜修饰电极上的电化学氧化行为,实验表明,该膜对葡萄糖的氧化有催化作用。     

电化学石英晶体微天平研究重氮盐的电还原过程

采用压电电化学石英晶体微天平(EQCM)技术研究了硫酸重氮盐在裸金电极(Au)和多壁碳纳米管(MWCNTs)修饰金电极上的电还原行为,比较了2种电极上电沉积质量和稳定性。结果表明,相同循环伏安扫描条件下,重氮盐在金电极和MWCNTs/Au电极上的工作曲线还原峰电位相同,后者的初始峰电流低于前者,QCM数据显示重氮盐在MWCNTs/Au电极上沉积速度优于金电极,饱和沉积量是金电极上的3倍,表明碳纳米管催化了还原过程并增大了电极的表面积;在磷酸中性缓冲溶液中浸泡7 d后,重氮盐修饰后的MWCNTs/Au电极表面质量变化比金电极小0.28ng,表明修饰后的MWCNTs/Au电极略稳定。     

聚3,4-乙撑二氧噻吩/金复合电极的制备及其在多巴胺检测中的应用

在水溶液中,以对甲苯磺酸钠为支持电解质,在氧化铟锡导电玻璃上,采用电化学恒电位极化法制备聚3,4-乙撑二氧噻吩(PEDOT)修饰电极。通过电化学循环伏安法,在PEDOT电极上沉积金纳米颗粒(Au NPs),制得PEDOT/Au复合修饰电极,用于多巴胺(DA)的电化学检测。考察了PEDOT/Au复合修饰电极中Au NPs的沉积量对DA电化学检测响应的影响,同时研究了在干扰物质抗坏血酸(AA)和尿酸(UA)存在时,PEDOT/Au复合修饰电极对DA的检测。结果表明,在中性p H溶液中,利用PEDOT/Au复合修饰电极,采用差分脉冲伏安法检测DA的线性范围为5×10-6~1×10-4mol/L,最低检测限可达1×10-8mol/L,且能有效排除AA和UA的干扰,实现三者的同时检测。     

聚3,4-乙撑二氧噻吩/金复合电极的制备及其在多巴胺检测中的应用

在水溶液中,以对甲苯磺酸钠为支持电解质,在氧化铟锡导电玻璃上,采用电化学恒电位极化法制备聚3,4-乙撑二氧噻吩(PEDOT)修饰电极。通过电化学循环伏安法,在PEDOT电极上沉积金纳米颗粒(Au NPs),制得PEDOT/Au复合修饰电极,用于多巴胺(DA)的电化学检测。考察了PEDOT/Au复合修饰电极中Au NPs的沉积量对DA电化学检测响应的影响,同时研究了在干扰物质抗坏血酸(AA)和尿酸(UA)存在时,PEDOT/Au复合修饰电极对DA的检测。结果表明,在中性p H溶液中,利用PEDOT/Au复合修饰电极,采用差分脉冲伏安法检测DA的线性范围为5×10-6¹×10-4mol/L,最低检测限可达1×10-8mol/L,且能有效排除AA和UA的干扰,实现三者的同时检测。     

K_3[Fe(CN)_6]溶液中普鲁士蓝修饰电极的制备及其对H_2O_2的电催化还原

应用循环伏安法和微分脉冲伏安法研究了K3[Fe(CN)6]溶液中普鲁士蓝(PB)修饰电极的制备及其电化学行为。结果表明,在连续循环伏安扫描的条件下,K3[Fe(CN)6]会在对电极上发生解离生成Fe3+,Fe3+可以跟单室电解池三电极体系中的[Fe(CN)6]3-生成在Au电极表面有较强吸附作用的PB,所获得的PB修饰电极的稳定性受介质和外加电位的影响。修饰电极上的PB在c(KCl)=0 2mol/L中性或弱酸性溶液中于-0 10 5V较稳定,而在c(H2SO4)=1 0mol/L溶液中PB会在Au电极上溶出;于-0 11 5V扫描时PB也会在Au电极上溶出。尤为重要的是,所获得的PB修饰电极对H2O2的还原既有很好的间接电催化作用,又可以降低H2O2在其上反应的活化能,对H2O2还原反应的电子传递起到促进作用。     

cdSe_xTe_(1-x)薄膜电极光溶解性能的研究

用循环伏安法对半导体Cdse_xTe_(1-x)薄膜电池的光溶解性能进行了研究。在1mol/L KCl溶液中测量光溶解产物的阴极还原特性,考察了在多硫化钠,多硫化钾及铁氰化钾溶液中的光腐蚀行为。用此方法还研究了薄膜电极表面的光刻蚀过程和pH的影响,并用X射线光电子能谱分析光刻进行不同时间后,电极表面发生的变化。     

拉氏变换阻抗分析测量CdSe薄膜电极的表面态

在光电化学光能转换的研究中,由于多种因素在半导体/溶液界面形成了各种性质和作用不同的表面态,在界面的电荷和能量转移中起着重要作用,对光电转换性能产生较大的影响。对于多晶半导体——作为具有实用前景和目前深受重视的光电转换材料,由于存在较多的晶格缺陷和晶粒界面,在表面形成了浓度较高的表面态,这些表面态可作为光生电子空穴的复合中心,是造成多晶材料光电转换效率低于单晶材料的主要原因。因此测量和研究半导体/溶液界面的表面态能量分布,性质及作用对研究光电转换过程的机理,特别是对改善多晶半导体的性能都具有直接的重要意义。     

Modelling the mode of operation of PEMFC electrodes at the particle level: influence of ohmic drop within the active layer on electrode performance

Numerical modelling of charge transfer using the finite element method within the whole active layer of proton exchange membrane fuel cell (PEMFC) electrodes is proposed in order to study the electrocatalyst utilization as characterized by the effectiveness factor. In this way, two modified approaches based on the thin film and agglomerate models are developed for studying ionic ohmic drop effects in the active layer at both the electrolyte layer and electrocatalyst particles scales. The catalyst phase is considered to be a network of spherical nanoparticles instead of the classical representation as a uniform distribution over a surface (thin film model) or in a volume (agglomerate model). Simulations point out unexpected effects at the local level due to the discrete distribution of the catalyst phase as nanoparticles. Finally, the results are applied to the practical case of oxygen reduction and hydrogen oxidation.     

CuTsPc分子膜／P—si（11 1）界面的光致电荷转移及其机制研究

本文利用L-B技术,在p-Si(111)基底上铺展了单层厚度只有6的CuTSPc超薄分子膜(简称超分子膜)和具有C_(18)脂链间隙的CuTSPc L-B膜两种膜系,首次观察到了CuTSPc分子膜在这种特定界面中的表面光电压谱。并且发现,当CuTSPc仅为一个单分子层时,这两种膜系的表面光伏效应最强。我们的研究结果表明,只有紧邻半导体基底的一个单分子层厚度的染料分子对光致界面电荷转移起关键作用。最后在实验上证实这种电荷转移是电荷直接注入机制,而非间接注入机制。     

Impact of Functionalized Polystyrenes as the Electron Injection Layer on Gold and Aluminum Surfaces: A Combined Theoretical and Experimental Study

At metal/organic interfaces, the insertion of an organic monolayer can significantly modify the surface properties of the substrate, especially in terms of charge injection across the interface. Herein, we study the formation of an insulating monolayer of morpholine or amine-functionalized polystyrene on Al(111) and Au(111) surfaces and its impact on surface work-function and charge injection. First-principles calculations based on Density Functional Theory have been carried out and point to a significant decrease in the work-function of modified metal surfaces; this is in very good agreement with ultraviolet photoemission spectroscopy measurements performed on the Au(111) surface. In addition, a bilayer cathode, consisting of a thin film of high-work-function metal, such as Al and Au, and a layer of amine-functionalized polystyrene, was also fabricated and tested in organic light-emitting diodes. Such bilayer structures exhibit substantially enhanced efficiency when compared with controls without the functionalized polymers. Our combined theoretical and experimental investigation gives insight into how a thin layer of a commodity polymer can be used to transform rather high-work-function metals into high-performance cathodes to provide efficient electron injection.     

Electrochemical fabrication and electrocatalytic characteristics studies of gold nanopillar array electrode (AuNPE) for development of a novel electrochemical sensor

Gold nanopillar array electrodes were prepared by electrochemical deposition of gold into the nanopores of anodic aluminum oxide membrane placed onto the gold thin film electrode surface, which was in advance modified with cysteamine self-assembled monolayer as an anchoring layer. The Au nanopillar electrode is electrochemically stable and consists of highly dense, upstanding pillars assembled on the cysteamine monolayer. The structural morphology and chemical composition of the nanoarray electrode was characterized by field emission scanning electron microscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. Electrochemical measurements indicate that the Au nanopillar electrode possesses high electrocatalytic activities in the reduction of hydrogen peroxide and molecular oxygen, especially in glucose oxidation due to its higher electroactive surface area. The electro-oxidation studies of several electroactive neurotransmitters demonstrate that the nanopillar electrode can be utilized as a promising material for the construction of novel electrochemical sensor.     

Electrochemical solar cells with polypyrrole-coated CdSe sintered electrodes

A thin layer of polypyrrole was formed on sintered CdSe electrodes. The photoelectrochemical properties of bare CdSe and P-Py/CdSe electrodes were studied in electrolyte with the redox couple [K₃Fe(CN)₆]. The results were explained by assuming that a p-n junction is formed on CdSe electrodes with polypyrrole working as a p-type semiconductor.     

Electrocatalytic Reduction of Oxygen on a Pd Ad-Layer Modified Au(111) Electrode in Alkaline Solution

Oxygen reduction was studied on palladium, cadmium and zinc ad-atom modified single crystal Au(111) electrodes. The electrodes were modified by underpotential deposition process and their activity towards oxygen reduction was studied in alkaline media by voltammetry. The reduction peaks obtained were compared with those of bare Au(111), Pd disc and bulk deposited Cd electrodes. Enhanced catalytic activity of the Au(111) electrode in the presence of Pd, Cd and Zn ad-layer can be attributed to a change in surface charge and energy by ad-layer formation. In oxygen saturated medium a well defined sharp reduction peak was observed at ?0.12 V for 1/5 ML Pd ad atom modified Au(111) electrode while it was positioned at ?0.18 V on a Pd disk electrode. The best shift in reduction peak potential was obtained with 2/5 ML Pd ad atom modified Au(111) electrode with similar current density of Pd disc electrode.