电解0.1m1/LCuS04溶液 阴极反应(-):Cu2++2e=Cuy 阳极反应(+):2H2O=O2↑+4H+4e 电池反应:2Cu2++2H2O=2Cu+O2+4H+ 0.059 E(CuCu2)=0.337+-lCu2]=0.307(V) 0.059 E(O2H2O)=1.29+g O,H 4°田H2O2 1.22(V) 原电池电动势为:E=122-0.307=091(平 图电解电池 n=0.8v Over potential, E(02/H20 =2.021 E外=(E阳+阳 )-(E阴十引阴)+iR E=2.02-0.307=1.65V
电解 0.1 mol/L CuSO4 溶液 阴极反应（-）：Cu2+ + 2e ＝ Cu 阳极反应（+）：2H2O ＝ O2 + 4H+ +4e 电池反应：2Cu2+ + 2H2O = 2Cu + O2 + 4H+ 1.22 (V) [H O] [O ][H ] lg 4 0.059 (O /H O) 1.229 lg[Cu ] 0.307 (V) 2 0.059 (Cu/Cu ) 0.337 2 2 4 2 2 2 2 2 = + = = + = + + + E E 原电池电动势为：E= 1.22 - 0.307 = 0.91 (V) = 0.8V Over potential, E(O2 /H2O)=2.02V E = 2.02-0.307=1.65V E外 = （E阳 + η阳）-（E阴 + η阴） + iR
05 a 0,4 03 D 3.0 外加电压(矿 a’理论计算曲线a实测曲线 n’理论分解电压D实际分解电压 电解C溶液的电流-电压曲线
Voltammetry Voltammetry comprises microelectrolysis techniques in which the working electrode potential is forced by external instrumentation to follow a known potential-time function and the resultant current- potential and current-time curves are recorded and analyzed to obtain information a bout the solution composition. Depending on the shape of the potential-time perturbing (ta)signal and on the mode of the analyte transport, voltammetric techniques can be subdivided as Linear potential sweep volatmmetry(线性电位扫描伏安法) Potential step method(电位阶跃法) Hydrodynamic methods(流体动力学方法) Stripping voltammetry(溶出伏安法)
Voltammetry comprises microelectrolysis techniques in which the working electrode potential is forced by external instrumentation to follow a known potential-time function and the resultant currentpotential and current-time curves are recorded and analyzed to obtain information about the solution composition. Depending on the shape of the potential-time perturbing (扰动)signal and on the mode of the analyte transport, voltammetric techniques can be subdivided as : Linear potential sweep volatmmetry （线性电位扫描伏安法） Potential step method （电位阶跃法） Hydrodynamic methods （流体动力学方法） Stripping voltammetry （溶出伏安法） Voltammetry
Chapter3 Voltammetry伏安法 Section 1 Linear potential sweep volatmmetry(线性扫描伏安法) Section2 Stripping voltammetry(溶出伏安法)
Section 1 Linear potential sweep volatmmetry （线性扫描伏安法） Section 2 Stripping voltammetry （溶出伏安法） Chapter 3 Voltammetry 伏安法
Section 1 Linear sweep volatmmetry(LSV)(线性扫描伏安法) 1. LSV with Dropping mercury electrode (Dme) Polarography极谱法 2. LSV with stationary electrodes
Section 1 Linear sweep volatmmetry (LSV)（线性扫描伏安法） 1. LSV with Dropping mercury electrode (DME) 2. LSV with stationary electrodes Polarography 极谱法
m 1. Polarography →一一----单一-→ A 经典极谱仪 甘汞电极 滴汞电极 Cation阳离子 Cathode阴极 A mIon 阴离子 Anode阳极
1.Polarography 经典极谱仪 Cation 阳离子 Cathode 阴极 Anion 阴离子 Anode 阳极
Dropping mercury electrode ---一--一-----一---------- Capillary length 10-20cm inside diameter: 0. 05mm Life time 2 to 6 second 作业: The advantages of dme:Ps
Dropping mercury electrode Capillary length: 10-20cm, inside diameter: 0.05mm Life time 2 to 6 second 作业：The advantages of DME: P43
103mo/LPb2+溶液 0.1 mol/LHCI supporting electrolyte The reduction of pblt at DMe: A) Pb+2e>Pb(Hg)E(Pb2+/Pb)=-0.126V Eappr Etir=Eeg+n +iR 甘 滴 汞 Open potential suppose n=0,iR=0 极 极上 appl eqdme rej,EDME= applref 已知:E参比=+0.24V 外加电压:-0,4V(0V,0.34V(-0.1V -0.44(0.2V),-0.54V(-0.3V),-0.64V(-0.4V) -0.74V(-0.5V),-084V(-0.6V),-0.94V(-0.7V 当E app 0.37VE DME 0.13V
10-3 mol/L Pb2+ 溶液 0.1 mol/L HCl supporting electrolyte The reduction of Pb2+ at DME: 2 ( ) 2 Pb + e → Pb Hg + 已知：E参比= +0.24V 外加电压：-0.24V(0V), -0.34V(-0.1V), -0.44V(-0.2V), -0.54V(-0.3V), -0.64V(-0.4V) -0.74V(-0.5V), -0.84V(-0.6V), -0.94V(-0.7V), Eappl=E+iR=Eeq+ +iR Eeq Open potential suppose = 0, iR = 0 Eappl= Eeq = EDME– Eref , EDME = Eappl+Eref 当 Eappl = - 0.37V EDME = -0.13V E0 (Pb2+/Pb) = -0.126V
20 极限扩 散电流 残余电流 0-0.2A-04-0 08-10-12r 分解电压 半波电位 P52fig73-195种金属离子混合液的极谱图
P52 fig. 7.3-19 5种金属离子混合液的极谱图
Three current regions of a polarogram: (P4) residual current region残余电流 2 charge transfer controlled region电荷转移控制电流 3 limiting current region极限扩散电流
Three current regions of a polarogram : (P47 ) 1.residual current region残余电流 2.charge transfer controlled region 电荷转移控制电流 3.limiting current region 极限扩散电流