大学电分析课件液液界面电化学及电分析化学简介

1、大学电分析课件液液界面电化学及电分析化学简介1.液/液界面电化学的发展历史2.液/液界面电化学的基本原理3.液/液界面电化学的主要研究方法及仪器设备4.液/液界面电化学的现状5.液/液界面电化学的未来展望主要内容大学电分析课件液液界面电化学及电分析化学简介参考书和文献：1. 液/液界面电化学， P.Vanysek 著， 罗颖华 译，汪尔康 审校， 吉林大学出版社， 1987年2. H.H.Girault and D.J.Schiffrin, in Electroanalytical Chemistry, A.J.Bard., Ed.; Vol:15, p.1, Marcel Dekker, N

2、ew York ,19893. H.H.Girault, in Modern Aspects of Electrochemistry, J.O.Bockris, B.E.Conway, R.E.White, Eds.; Plenum Press, New York, 1993, Vol:25, p.14. J.Koryta, Electrochemical polarization phenomena at the interface of two immiscible electrolyte solutions. Electrochimica Acta, 24(1979)293-3005.

3、J.Koryta, Electrochemical polarization phenomena at the interface of two immiscible electrolyte solutions. II. Progress since 1978. Electrochimica Acta, 29(1984)445-4526. Volkov A G, Deamer D W. Liquid-liquid interfaces. Theory and Methods. California: CRC Press, 1996.大学电分析课件液液界面电化学及电分析化学简介1. Brief

4、Introduction of Electrochemistry at Liquid/Liquid Interfaces应用电化学方法研究电荷在液/液界面上的转移反应 - 液/液界面电化学.它是电化学及电分析化学的一个重要分支，也是生物电化学的一个重要组成部分。Charge (electron and ion) transfer across Liquid/Liquid (L/L) interfaces, or Oil/Water interfaces, or the interface between two immiscible electrolyteSolutions (ITIES) i

5、s one of the most fundamentalphysicochemical processes. 大学电分析课件液液界面电化学及电分析化学简介Brief history:1902, Nernst and Riesenfeld1906, Cremer pointed out that the analogy between the water/oil/water concentration cells and biological membrane1939, Verwey and Niessen, first theoretical paper on the electrical

6、double layer and potential distribution at ITIES1970s, Gavach et al. in France 首先认识到 L/L 界面在一定的实验条件下可以被极化， 并用Chronopotentiometry 对一些简单离子在Water/Nitrobenzene (W/NB)的转移行为进行了研究。同时用Modified Verwey-Niessen (MVN)对实验结果进行了分析。随后 Koryta et al. 发展了滴水电极及相应的实验装置，并首先研究了中性载体加速离子转移反应。Samec et al. in 1979设计了具有iR降补偿性质

7、的四电极恒电位仪，用来记录离子转移反应的伏安图。这样L/L界面电化学才在世界各地得到普及和蓬勃发展。大学电分析课件液液界面电化学及电分析化学简介1980s, 汪尔康先生等是中国第一个从事L/L界面电化学研究的group1986, Girault et al. 第一个将微-L/L界面支持在Micropipettes 上1991, Corn et al. 应用SHG研究L/L界面1995，Mirkin and Bard et al. 应用SECM 研究L/L界面1997, Y.Shao et al. 第一个将纳米级-L/L界面支持在 Nanopipettes 上最近几年各种光谱技术也应用于此领域的

8、研究大学电分析课件液液界面电化学及电分析化学简介WWElectrodeOilGold，Pt，C NB 1,2-DCEThe difference between L/L interface andElectrode/Electrolyte interface大学电分析课件液液界面电化学及电分析化学简介Electrochemistry of L/L interfacesO + e = RRedox ReactionsO + e = RRedox ReactionsMZ (w) = MZ(o)Ion Transferthe conventional ElectrochemistryThe diff

9、erence between Electrochemistry at L/L interface and the conventional Electrochemistry大学电分析课件液液界面电化学及电分析化学简介Chemical sensorsElectrochemistryH+，pHK+,Na+,NH4+Cl-, Ac+O + e = RElectroactivespeciesNonelectroactivespeciesL/L InterfaceElectrochemistry at L/L Interfaces is the bridge between the convention

10、al electrochemistry and Chemical sensors大学电分析课件液液界面电化学及电分析化学简介 Electrochemistry at Liquid/Liquid Interfaces is a fast way to select receptors for making chemical sensors大学电分析课件液液界面电化学及电分析化学简介ElectrodeOBiological Membrane ModelL/L InterfaceElectrode/electrolyte Membrane/solutionArtificial ,supported

11、membrane and BLM大学电分析课件液液界面电化学及电分析化学简介Electrochemistryat L/L InterfacesNew Branch ofElectrochemistryMechanism of Chemical sensorsPhase Transfercatalytic reactionsMimickingbiologicalmembranesResearch Significance and applicationsof Electrochemistry at L/L InterfacesExtraction Mechanism大学电分析课件液液界面电化学及

12、电分析化学简介2.液/液界面电化学的基本原理2.1.Equilibrium conditions and Nernst potentialIn general at Liquid/Liquid interfaces, there are two types of charge partition:(A) the transfer of an ion M with the charge number z from the phase w to the phase o and the reverse:MZ(w) = MZ(o)M+(w) + L(o) = ML+(o)(B) the electro

13、n transfer between a redox couple O1/R1 in the phase w and a redox couple O2/R2 in the phase o, which can be represented as:O1(w) + R2(o) = R1(w) + O2(o)大学电分析课件液液界面电化学及电分析化学简介Nernst Equations大学电分析课件液液界面电化学及电分析化学简介Liquid/Liquid interfaces have been classified into the ideal-polarized interface and no

14、-polarized interface.2.2.Single ion Gibbs energy of transferTATB assumption大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介2.3.Solvation of IonBorn equation2.4.Interfacial structure and the ion transfer mechanism(A)MVN MODEL(B)GS MODEL大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介2.5

15、.Solvents and base electrolytesThere are over 20 organic solvents which have been tested in the ITIES studies so far. As pointed out by Koryta et.al., the following three requirements have been commonly used to choose the organic solvent:(1). The solubility of solvent in water and water in the solve

16、nt must be very small.(2). The solvent must be sufficiently polar to promote sufficientdissociation of the supporting electrolyte and thus keeping enough conductivity of the solution.(3). The density of the solvent should differ significantly from that of aqueous phase in order to get a physically s

17、table l/l interface.大学电分析课件液液界面电化学及电分析化学简介At present, the most commonly used organic solvents are nitrobenzene(NB) and 1,2-dichloroethane (1,2-DCE). Some othersolvents have been tried in the past two decades, for example, propiophenone, 4-isopropyl-1-methyl-2-nitrobenzene, dichloro-methane,nitrotule

18、ne, chloroform, aniline etc. In order to get more flexible choice, organic solvent mixtures have been also employed, for example, nitrobenzene + chlorobenzene, NB + benzonitrile and NB + benzene.Base electrolytes: TBATPB (tetrabutylammonium tetraphenylborate), TBATPBCl, CVTPB, BTPPATPB (Bistriphenyl

19、phosphoranylideneammonium tetraphenylborate)大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介3.液/液界面电化学的主要研究方法及仪器设备Almost all the instruments have been used to study classical electrochemistry can be used to investigate the charge transfer at liquid/Liquid interfaces.4-electrode pot

20、entiostat - Big iR dropaqueous solution dropping (ascending) electrodetwo-electrode system - microelectrodesRecently, we developed a novel technique to study ITIES withthree -electrode setup with the help of the phase ratio. Thus, allelectrochemical labs can do research on this subjects.大学电分析课件液液界面电

21、化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介2-电极系统大学电分析课件液液界面电化学及电分析化学简介应用于液/液界面电化学研究的升水电极- 四电极系统大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介新的技术，例如: SHG(Second harmonic generation) microelectrodes, micropipettes and nano-pipettes SECM Femto-laserSimulationsThin films 现已用在L/L Interfaces 的研

22、究。各种电化学方法和技术大学电分析课件液液界面电化学及电分析化学简介4.液/液界面电化学的现状Structure: MVN Model and GS Model Mechanism: Facilitated ion transfer mechanismKinetics: Butler-Volmer equation, Marcus theoryNanometeropipettesSECMApplications:Thin films (solar cell, drug delivery)大学电分析课件液液界面电化学及电分析化学简介目前国际上液/液界面电化学研究存在的主要问题1. 界面结构未知!

23、 MVN模型和混合溶剂层模 型(GS)2. 可供选择作为有机相的有机溶剂数目有限3. 没有很好的获取转移反应动力学的实验手段4. iR(i-电流，R-电阻，iR降是由于溶液中电阻 所引起的干扰)降及充电电流较常规电化学更 加严重大学电分析课件液液界面电化学及电分析化学简介How to solve these ProblemsMicroelectrodes:Solid and Nano- andMicropipettes+ScanningElectrochemical Microscopy, SECM大学电分析课件液液界面电化学及电分析化学简介Electrochemistry at L/L In

24、terfacesArtificial Membrane/Electrolyte InterfacesBLMArtificial Membrane andBiosensorsModified L/L InterfacesMicroelectrodesNano- and MicropipettesSECM大学电分析课件液液界面电化学及电分析化学简介The SEM diagrams ofNano- and MicropipettesMicropipettesNanopipettes大学电分析课件液液界面电化学及电分析化学简介MicropipettesTheta ()Micropipette大学电分析

25、课件液液界面电化学及电分析化学简介The SEM diagrams ofNano- and MicropipettesMicropipettesNanopipettes我们group可以制备内径从几个nm到十几个m的玻璃纳、微米管大学电分析课件液液界面电化学及电分析化学简介Aqueous PhaseOrganic PhaseAqueous PhaseOrganic PhaseAsymmetric Diffusion Field大学电分析课件液液界面电化学及电分析化学简介TBATPB as supporting electrolyte in DCETBATPBCl as supportingel

26、ectrolyte in DCEBTPPATPB as supportingelectrolyte in DCEMicropipette as a toolto determine the ionic species limiting thepotential window at L/LInterfacesTBATPB (Tetrabutyalammoniumtetraphenylborate)TBATPBCl(tetrabutyl-ammonium tetrakis4-chlorophenylborate)BTPPATPB (Bistriphosphor-anylideneammonium

27、tetraphenyl-borate)1,2-dichloroethane (DCE)大学电分析课件液液界面电化学及电分析化学简介Ag/AgCl/0.01MTBACl/0.25mMDB18C6+0.01MTBATPBCl/0.01MKCl/AgCl/AgIdentify the different mechanisms大学电分析课件液液界面电化学及电分析化学简介ACTTOCTICTIDwowowowoIdentify of different mechanisms of facilitated ion transfers大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及

28、电分析化学简介Idisk =4nFaDCIpip =3.35nFaDCWhy Ipip is about 2.63 times bigger than Idisk ?Silanization plays very important rolehere!Anal.Chem., 1998, 70,p3155-3161大学电分析课件液液界面电化学及电分析化学简介3.4E-9大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介Nanometer-sized L/L Interface 纳米管NanopipetAqueous Phase大学电分析课件液液界面电化学及电

29、分析化学简介Nano-ITIESko from 0.1cm/s to 10cm/s A 54nm radiusB 5nm radiusJ.Am.Chem.Soc., 1997, 119, 8103K+(w) + DB18C6(DCE) = K+DB18C6(DCE) 大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介J.Am.Chem.Soc., 1998, 120, 12700科学意义和创新点：第一次在实验上实现了非氧化还原物质的Generation/Collection Mode。 对于测量反应中间产物和快速电荷转移反应动力学有重要意义。大学电分析课件

30、液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介The photo of -micropipette under microscope大学电分析课件液液界面电化学及电分析化学简介大学电分析课件液液界面电化学及电分析化学简介“ Non-solution” L/L Interface Electrochemistry大学电分析课件液液界面电化学及电分析化学简介Generator (1) and collector(2)voltammograms of the transfer of K+ between waterand DCE containing DB18C6ig v

31、s. Eg and ic vs. Eg curvesobtained with an aqueous film linking two barrels of the -pipet大学电分析课件液液界面电化学及电分析化学简介Detection of ammonia in the air. Cyclic voltammogams obtained witha -pipet exposed to air (1) and ammonia vapor above its 2M solution大学电分析课件液液界面电化学及电分析化学简介The potential windows depend upon the amount of Agar. Scan rate is 30mV/s. The radius of the micropipette is 4m，curves1、2、3 and 4 corresponding to 25%、10%、1% and0.5% of Agar, respectivelyAgar-water