ELECTROCATALYSIS OF THE REDUCTION OF TRICHLOROACETIC-ACID BY POLYPYRROLE COBALT PORPHYRIN MODIFIED ELECTRODES

In the present study a chemically modified (with a pyrrole group) coba lt porphyrin that is immobilized by electropolymerization on a vitreou s carbon electrode is used for the electrocatalytic reduction of trich loroacetic acid (a toxic compound widely used in Mexico as a plaguicid e) and to improve the electrochemical detection of the latter. The res ults obtained by cyclic voltammetry show an important catalytic effect , i.e. the reduction potential of this compound is decreased by 1.0 V. Even though the catalytic efficiency of the modified electrode depend s on the film synthesis conditions, the studies done by cyclic and by rotating disk electrode voltammetry show that the presence of the thin film (45 equivalent monolayers or 18 nm thickness) does not provoke a ny apparent diffusional limitation in the catalytic process. The prese nt work constitutes the first example of a heterogeneous catalysis usi ng electrodes that are modified with electropolymerizable porphyrins i n the reduction of a toxic organochlorinated compound.