SURFACTANT-INTERCALATED CLAY FILMS CONTAINING METAL PHTHALOCYANINES

We previously showed that clay-surfactant films containing metal phthalocyanines catalyze electrochemical reductive dechlorinations. Cobalt(II) phthalocyanine (Co(II)Pc) was a much better catalyst than the corresponding iron complex. This paper reports studies of these catalytic films by spectroscopic, X-ray, and electron microscopic methods. Scanning electron microscopy cross sectional images of films of didodecyldimethylammonium bromide, clay, and Co(II)Pc were considerably different from the stacked layers observed for pure composites. Previously observed phase transitions are characteristic of surfactant bilayers. The general morphology of these films appears to feature a heterogeneous mixture of Co(II)Pc crystals and surfactant bilayers intercalated between clay layers. Electronic spectra and X-ray diffraction patterns suggest that iron phthalocyanine (Fe(II)Pc) is present in oxidized forms in these films. Co(II)Pc films are better dechlorination catalysts partly because Co(II)Pc remains intact in the films, while Fe(II)Pc is decomposed.