四磺酸酞菁钴-DDAB表面活性剂薄膜电极的电化学与电化学催化研究

四磺酸酞菁钴配合物阴离子(CoPcTS_4-)在水溶液中可借助离子交换进入阳离子表面活性剂双十二烷基二甲基溴化铵(DDAB)薄膜,从而形成CoPcTS_4-DDAB薄膜电极.循环伏安法表明,该薄膜电极在pH7.0的空白缓冲溶液中十分稳定,有两对准可逆的还原氧化峰,其中第一对峰的E_pc1=-0.28V,E_pa1=-0.18V(vs.SCE),为中心离子Co(II)Co(I)的还原氧化峰;第二对峰的E_pc2=-1.30V,E_pa2=-1.18V,为酞菁环的还原氧化峰.应用循环伏安法估计了该薄膜体系的电荷传递扩散系数D_ct和表观非均相电极反应速率常数k^o'.CoPcTS_4-DDAB薄膜电极可用于对三氯乙酸(TCA)的电化学催化还原.催化电流与TCA浓度在4×10^-5～1×10^-3molL范围内成线性关系.

Electrochemistry and Electrochemical Catalysis of Cobalt Phthalocyanine Tetrasulfonate-DDAB Surfactant Film Electrodes

Cobalt phthalocyanine tetrasulfonate (CoPcTS_4-) anions in aqueous solutions could enter the films of cationic surfactant didodecyldimethylammonium bromide (DDAB) films by ion exchange and form CoPcTS_4--DDABfilm electrodes. Cyclic voltammetry (CV) showed in pH_7.0 blank buffers, the films were quite stable and had two pairs of quasireversible redox peaks. The first pair shown at E_pc1= -0.28 Vand E_pa1=-0.18 V (vs. SCE) was attributed to the redox couple of Co(II)/Co(I) of CoPcTS_4-, while the second set at E_pc2=-1.30 Vand E_pa2=-1.18 Vcorresponds to the redox process of phthalocyanine ring. The charge transport diffusion coefficient, D_ct, and apparent heterogeneous electrode reaction rate constant, k^o', were estimated by CV. CoPcTS_4--DDAB films could be used to catalyze electrochemical reduction of trichloroacetic acid (TCA). Catalytic current had a linear relationship with the concentration of TCAin the range of 4×10^-5-1×10^-3 mol/L.