Electrochemistry Reference books南京大学《物理化学》，北京大学《物理化学》Atkins' Physical Chemistry, 7th Ed., Peter Atkins, Julio de Paula, Oxford University Press.课件下载网址/下载密码: jg4103学习物理化学（电化学）的特点和要点1.通过自学接受知识2.学习严谨推理和归纳本领3.掌握电化学的定位和特点4.学习分析问题的方法Physical ChemistryThermochemistry，Electrochemistry, Photochemistry，…Colloid Chemistry，Catalysis，Computational Chemistry，…Electrochemistry PhysicalChemistry Solution electrochemistry(electrolyte solution)Equilibrium stateelectrochemistryThermodynamicsSolid electrochemistry Photoelectrochemistry BioelectrochemistryQuantum Chemistry Statistical ThermodynamicsThree Characteristics of Electrochemistry1. Long history 1. Long history2. Wide application2. Wide application3. Electrochemical phenomenaexist everywhere3. Electrochemical phenomena exist everywhereElectrochemistry is over 200 Years Old! Luigi Galvani–Physician/Anatomist –“Animal Electricity”(1791)1799Volta Pile by A.Volta The most important giftto 19th century!Electrochemistry ScienceVolta Pile1. Long historyAlesandro Volta –“Metallic Electricity”(1800)The Characteristics of Electrochemistry1. Long history1799Volta Pile1834Faraday’s Law1887Journal of Physical Chemistry2. Wide Applications in Scientific Areas 2. Wide Applications in Scientific Areas Energy （battery, fuel cell, …)Materials（electrolysis, electrodeposition, corrosion…）Life（heart-electroencephalogram, electrophoresis, …) Environment (sensor, waste treatment, …）Information（surface process, chip fabrication …）3. Electrochemical Phenomena Exist Everywhere 3. Electrochemical Phenomena Exist Everywherewater exists universally in our natural world→electrolyte solution →charged ions(i)μiα≠μiβi -charged particle→spontaneous charge transferbetween two phasesμiα≠μiβi -charged particle →spontaneous transfer between phases, forming potential difference(b)μi α≠μi βi -charged particle →charge transfer between two phases (c)excess charge at the interface →potential difference(a)→Electrolyte solution →charged ions iwater exists universally in our natural worldThe Characteristics of Electrochemistry 1. Long history2. Wide application3. Existing everywhere1. Long history2. Wide application3. Existing everywhere Charged particlesMultiphase systemsThermodynamic of Electrochemical Systems()∑∑==+=211αααααφμK i i i i i dn F z dn dGααααααααφμi i i dn F z dp V dT S G d )(~+++−=∑ααααφμF z n G i i n p T ii j +=⎟⎟⎠⎞⎜⎜⎝⎛∂∂≠,,~βαdGdG dG +=ααααφμF z n G i i n p T i i j +=⎟⎟⎠⎞⎜⎜⎝⎛∂∂≠,,~ββααφμφμF z F z i i i i +=+βαμμii ~~=Electrochemical PotentialββββφμF z n G i i n p T i ij +=⎟⎟⎠⎞⎜⎜⎝⎛∂∂≠,,~i i i iEquilibrium ：μi β+ z i F φβ= μi α+ z iF φαparticle i has same electrochemical potential in two phasesEquilibrium ：μi β+ z i F φβ= μi α+ z i F φαparticle i has same electrochemical potential in two phases αβμμi i =Two Concepts of Electrode Material / Electrolyte Zn|Zn 2+, SO 42-Pt|H 2,H+Fe|Fe 3O 4|Fe 2O 3|waterElectrode (Electrochemical）Reaction Special HeterogeneousOxidation/Reduction ReactionElectrode (Electrochemical）ReactionSpecial Heterogeneous Oxidation/Reduction Reaction Oxidation and Reduction take place in the different place separatelyThe strength and direction of electric field can change the activation energy and rate of reaction！！！Electrochemical Device Electrochemical cell (Cell)Reactions at negative electrodePb + H 2SO 4PbSO 4+ 2H + + 2eOxRedoverall reactionPb + PbO 2 + 2H 2SO 42PbSO 4 + 2H 2OOutput energyInput energyPbO 2 + H 2SO 4+ 2H + + 2ePbSO 4 + 2H 2ORed OxReactions at positive electrodeQ Fz M kQ m 1==QnzF =m -mass of product,Q -reaction charge, n -number ofmoles ，z -number of react electrons ，F -Faraday constant /rimain/heritage/faradaypage.jspQ Fz M kQ m 1==QnzF =The quantity of a substance produced by electrolysis is proprotional to the quantity of electricty used.Faraday Constant F(1891)F= 6.023×1023e/mol×1.602×10-19coulomb/electron =96486.7 coulomb/mol≈96500 c /molDiscovery of Electron (1897)Some Features of Faraday Law F is a fundamental physical constantQ = nzF1. Establishment of quantitative relationship ofelectricity used and chemical reaction2. Independent of electrode, environment,reaction condition.cathodeanode（inertia ）Silver cathode Silver anode electrolyse smeltCl 2Ag Fe 2+Na +H 2O Cl -OH -Ag +H 2ONO 3-Ag +Fe 3+Br +H 2O Ag +Br 2H 2e-e -iicathode anode (1) NaCl(2) AgNO 3(3) FeBr 3（inertia ）Q = n 1z 1F = n 2z 2F = •••= n i z i F(1) cathode: H 2O + e -→OH -+ 1/2H 2anode: Cl -→1/2Cl 2+ e -gas product (1) cathode: H 2O + e -→OH -+ 1/2H 2anode: Cl -→1/2Cl 2+ e -gas product (2) cathode: Ag + + e -→Ag solid productanode: Ag →Ag + + e-(2) cathode: Ag + + e -→Ag solid product anode: Ag →Ag + + e -(3) cathode: Fe 3+ + e -→Fe 2+liquid producanode: Br -→1/2Br 2 + e-(3) cathode: Fe 3+ + e -→Fe 2+liquid product anode: Br -→1/2Br 2 + e -Q = n 1z 1F = n 2z 2F = •••= n i z i FSome Features of Faraday lawQ = nzF1. Establishment of quantitative relationship ofelectricity used and chemical reaction2. Independent of electrode, environment,reaction condition.3. Applicable to multi-setup reaction（in series）Q = n1z1F = n2z2F = •••= n i z i F--cathode anode Silver cathode Silver anode--Some Features of Faraday’s lawQ = nzF1. Establishment of quantitative relationship ofelectricity used and chemical reaction2. Independent of electrode, environment,reaction condition.3. Applicable to multi-cell reaction（in series）4. Applicable to single cell with multi-reaction(in parallel).Electrolyte SolutionConductance, Conductivity,Molar Conductivity, Limiting Molar ConductivityHow to compare, measure and understand the electric conductivity of different electrolyte solutions?Differences of Two Types of Charge ConductorElectronic / Ionic ConductorConduct mechanism free electron cations, anions Form of charge simple multiple Charge quantity single various Charge interaction constant various Temperature dependence T ↑, R↓T↑, R↓The conductivity of electrolyte solution κL=The conductance of a 1 m3cube containing electrolytesolution.κ⎯geometry normalizedCu KCl CuO pure water glass (aq, 1 M)1081010-310-610-12κ= κobserve-κwater electrolyteWheatstone AC BridgeConductance Measurementconductance cellconductance cell Cell constant K cell = l / A = κ/ L = κR cellConductance MeasurementThe conductance cell is usually calibrated with standard KCl (potassium chloride ) solution.11.21.2890.14110.0147κ/ S m -11.00.10.010.0010C/ mol dm -3a.Obtain R of a solution with known κ→K cell = κR cel lb. Measure R of unknown solution R cell →κobsc.OH obsx2κκκ−=Conductance Measurementκκ3c⋅/dmmol。