Polycatechol, polycatechol/aluminum oxide and ternary nanocomposite conducting polymers of catecholaminophenol/ aluminum oxide were prepared by in situ electrocopolymerization method on gold electrodes for electrocatalytic activity toward coenzyme β-nicotinamide adenine dinucleotide (NADH) detection. First, the polycatechol (PCAT), poly-o-aminophenol (POAP), new poly (catechol-co-aminophenol) (P(CAT-co-OAP), new polycatechol/γ-Al2O3 (PCAT/γ-Al2O3), new poly-o-aminophenol/γ-Al2O3 (POAP/γ-Al2O3) and new poly (catechol- co-aminophenol)/γ-Al2O3 (P(CAT-co-OAP)/γ-Al2O3) nanocomposite conducting copolymer were electrochemically synthesized on gold electrodes and studied voltammetrically in aqueous media. Then, polymers, copolymers and nanocomposite films were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), in situ conductivity measurements and in situ UV–visible spectroelectrochemistry. The mechanism of the copolymerization process was proposed and discussed. Compared with the polymer and copolymers, the PCAT/γ-Al2O3 and P(CAT-co-OAP)/γ-Al2O3 nanocomposite conducting copolymer exhibits a good electrocatalytic activity toward the oxidation of NADH molecule with a high sensitivities, high selectivity, perfect stabilities and good regenerations. These properties makes the PCAT/γ-Al2O3 and P(CAT-co- OAP)/γ-Al2O3 electrodes promising candidates for detection of NADH.
