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生物电分析化学 Electroanalytical Chemsitry and Its Biological Applications 刘宏 2015 年秋

生物电分析化学 Electroanalytical Chemsitry and Its Biological Applications 刘宏 2015 年秋. 课程目标. 掌握核心概念和原理 具备在该领域的继续学习的能力. Syllabus. 双语教学 不点名，作业不计分 开卷考试 教师邮箱 : liuh@seu.edu.cn 答疑与讨论：河海院 121 室 课程网页 : http://www.liuhong.info/?page_id=211. 课程大纲. Overview of electrochemistry （电化学概论）

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生物电分析化学 Electroanalytical Chemsitry and Its Biological Applications 刘宏 2015 年秋

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  1. 生物电分析化学Electroanalytical Chemsitry and Its Biological Applications刘宏2015年秋

  2. 课程目标 • 掌握核心概念和原理 • 具备在该领域的继续学习的能力

  3. Syllabus • 双语教学 • 不点名，作业不计分 • 开卷考试 • 教师邮箱:liuh@seu.edu.cn • 答疑与讨论：河海院121室 • 课程网页:http://www.liuhong.info/?page_id=211

  4. 课程大纲 • Overview of electrochemistry（电化学概论） • Equilibrium (平衡) • Electrochemical Kinetics (电化学动力学) • Mass-transfer（传质） • Potential step/sweep techniques (电势阶跃/扫描技术) • Ultra-microelectrode (超微电极，UME) • Scanning electrochemical Microscope (扫描电化学显微镜，SECM) • Finite-element simulation of electrochemical processes (电化学过程的有限元模拟) • Applications：biomedical diagnostics， sensors, biofuel cell， brain research and single-cell studies（实际应用: 生物医学诊断、传感器、生物燃料电池、脑科学、单细胞研究）

  5. Textbook Allen Bard 教授 2013美国国家科学奖章 巴德（Bard A.J.），福克纳（Faulkner L.R.）著，邵元华 等译 化学工业出版社 2005-5-1

  6. Electrochemistry Electrochemistry is the study of chemical reactions which take place at the interface of an electrode, usually a solid metal or a semiconductor, and an ionic conductor, the electrolyte. These reactions involve electric charges moving between the electrodes and the electrolyte (or ionic species in a solution). Thus electrochemistry deals with the interaction between electrical energy and chemical change.

  7. Overview of electrochemistry • Electrochemical cell (electrolytic, galvanic) • Half cell and standard reduction potential • Nernst equation • Three-electrode cell • Potential step techniques (chronoamperometry, chronocoulometry) • Potential sweep techniques (LSV, CV)

  8. Electrochemical parameters • Charge (q) • Potential (E) • Current (i) • Capacitance (C) • Resistance (R) • Conductance (G)

  9. Electrochemical cell • Non-spontaneous • Consume power • Cell voltage < 0 • Spontaneous • Generate power • Cell voltage > 0

  10. Electrochemical cell • Battery discharge: galvanic cell • Battery charge: electrolytic cell

  11. Half Cell 1. 2. E = 0.340 V E = -0.763 V Cell voltage: 0.340 V - (-0.763 V) = 1.103 V thermodynamic, at standard conditions

  12. Nernst Equation E0’ – standard reduction potential R – gas constant R=8.314 (J/mol/K) T- absolute temperature T=273.15+t (K) n – electron transferred F – Faraday constant F= 96485 (C/mol) Co(x=0) – concentration of oxidized species CR(x=0) – concentration of reduced species X=0 means “on the electrode surface”

  13. Electrochemical Cells Three-electrode cell: Two-electrode cell: iR drop: EiRs= iRs If Rs=100 Ω, i=1mA, EiRs= 0.1V

  14. Reference Electrode E0’= 0.222 V vs. NHE

  15. Faraday’s Law • Faraday’s law: • Nonfaradaicprocesses • charging/discharging • Faradaicprocesses • redox (reducing/oxidizing) events n is number of moles (n = m/M) t is the total time the constant current was applied. z is the no. of electrons transferred.

  16. Non-Faradaic Processes

  17. Faradaic Processes

  18. Electrochemical Kinetics

  19. Mass Transfer Nernst-Plank Equation: Diffusion: Migration: Convection: If the solution is kept still and excess supporting electrolyte (KCl or KNO3) is added to the solution, the contribution of convection and migration can be negligible .

  20. Potential Step Techniques R Chronoamperometry： CO* O CO(x=0) O + ne- R Cottrell equation for a planar electrode: DO： diffusion coefficient of O CO： concentration of O

  21. Potential Sweep Techniques

  22. Non-Faradaic Processes Potential Sweep：

  23. Faradaic Processes

  24. Assignment • Select two half cells listed in the table on Page 13 to construct (a) an electrolytic cell and (b) a galvanic cell. Write down the anodic, cathodic and overall reactions. Calculate the cell voltages at (a) standard conditions and (b) if the concentration of every solute is 1.00 mM. • Explain why we want to use a three electrode system in a potential-step experiment. • A 0.1 cm2 electrode with Cd=20 mF/cm2 is subjected to a potential step under conditions where Rs is 1, 10, 100 Ω. In each case, what is the time constant, and what is the time required for the double-layer charging to be 95% complete? • Consider the nernstian half-reaction: • the i-E curve for a solution at 25 0C containing 2.00 mM A3+ and 1.00 mM A+ in excess electrolyte shows il,c = 4.00 mA and il,a = -2.40 mA. Sketch the i-E curve for this system.

  25. Assignment

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