Electrochemistry and electrochemical catalysis of cobalt phthalocyanine tetrasulfonate-DDAB surfactant film electrodes

Cobalt phthalocyanine tetrasulfonate (CoPcTS4-) anions in aqueous solutions could enter the films of cationic surfactant didodecyldimethylammonium bromide (DDAB) films by ion exchange and form CoPcTS4--DDAB film 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 V and E-pa1 = - 0.18 V (vs. SCE) was attributed to the redox couple of Co(II)/Co(I) of CoPcTS4-, while the second set at E-pc2 = -1.30 V and E-pa2 = -1.18 V corresponds 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, CoPcTS4--DDAB films could be used to catalyze electrochemical reduction of trichloroacetic acid (TCA), Catalytic current had a linear relationship with the concentration of TCA in the range of 4x10(-5)-1x10(-3) mol/L.