Fabrication of Metalloporphyrin-Polyoxometalyte Hybrid Film by Layer-by-Layer Method and Its Catalysis for Dioxygen Reduction

Through layer-by-layer method [tetrakis(N-methylpyridyl)porphyrinato] cobalt (CoTMPyP) and polyoxometalyte were alternately deposited on 4-aminobenzoic acid (4-ABA) modified glassy carbon electrode. The resulting organic-inorganic hybrid films were characterized by cyclic voltammetry (CV), UV/visible absorption spectroscopy, and atomic force microscopy (AFM). It was proved that the multilayer films are uniform and stable. CoTMPyP-containing multilayer films exhibit remarkable electrocatalytic activity for the reduction of O2. Rotating disk electrode (RDE) voltammetry and rotating ring-disk electrode (RRDE) voltammetry confirm that P2W18/CoTMPyP multilayer films can catalyze the four-electron almost reduction of O2 to water in pH>4.0 buffer solution, while SiW12/CoTMPyP multilayer films catalyze about two-electron reduction of O2 to H2O2 in pH 1–6 buffer solutions. The kinetic constants for O2 reduction were comparatively investigated at P2W18/CoTMPyP and SiW12/CoTMPyP multilayer films electrodes.