摘要
制备了磷钼杂多酸－Ｌ－半胱氨酸自组装超分子膜电极（Ｐ２Ｍｏ１８－Ｌ－Ｃｙｓ／Ａｕ）。采用水平衰减全反射（ＡＴＲ－ＦＴＩＲ）光谱表征了膜的组成。研究了该膜电极的电化学性质，发现它在１．０ ｍｏｌ／Ｌ Ｈ２ＳＯ４溶液中，于０．０～０．７Ｖ（ｖｓ．ＳＣＥ）间ＣＶ扫描出现两对稳定、可逆的氧化还原峰，其中峰电位分别为Ｅｍ１＝０．３３４ Ｖ，Ｅｍ２＝０．１８８Ｖ，对应着Ｐ２Ｍｏ１８Ｏ_(６２)^(６－)的两步２电子－２质子反应；计时库仑法计算了薄膜内的电子传递系数Ｄ为５．０１ × １０^（－８）ｃｍ２·ｓ～（－１）。该膜电极对酸性溶液中的ＮＯ_２~－有明显的电催化还原作用，初步探讨了电催化机理。用差分脉冲伏安法（ＤＰＶ）测定其还原峰电流与ＮＯ_２~－的浓度在２．０ ×１０^（－６）～２．０ × １０^（－４）ｍｏｌ／Ｌ范围内呈良好的线性关系，相关系数为０．９９５３，检测限５．０×１０^（－７）ｍｏｌ／Ｌ。该电极用于模拟水样中ＮＯ_２~－的测定，结果满意。
Super molecular film composed of Dawson-phosphomolybdic anions on L-cysteine self-assembled monolayer modified electrode was prepared by electrostatic adsorption. Fourier transform infrared studies were used to characterize the composition of super molecular film. Two reversible redox couples were observed in 1 .0 mol/L H2SO4 in the range of 0.0 .-0.7 V. Em1 = 0.334 V, Em2 = 0.188 V, which attributed to two-electron and two-proton electrochemical processes of P2 Mo18 O_(62)^(6-). Charge transfer coefficient was 5.01 × 10^(-8) cm2 /s. Moreover, the super molecular film showed good catalytic activity for the reduction of NO_2^-in acidic solution and the catalytic mechanism was described. The catalytic current of NO_2~ vs. its concentration had a good linear relation in the range of 2.0×10^(-6)-2.0 × 10^(-4) mol/L, with the correlation coefficient of 0.9953 by differential pulse voltammetric response. Detection limit was 5.0 × 10 ^(-7) mol/L. The modified electrode has been used for the determination of NO_2^-in wastewater.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
2002年第2期178-182,共5页
Chinese Journal of Analytical Chemistry
基金
湖北省自然科学基金资助课题(No.2000J007)
