Fabrication of novel polycatechol/aminophenol/aluminum oxide ternary nanocomposite electrode and its electrocatalytic applications

Highlights: • Several polymer nanocomposites of catechol/aminophenol/γ-Al₂O₃ are synthesized. • Polymer, copolymer and nanocomposites were characterized successfully. • Polymers were used for electrocatalytic activity toward NADH detection. • Sensors show high sensitivity, selectivity, stability and good regenerations. -- Abstract: Polycatechol, polycatechol/aluminum oxide and ternary nanocomposite conducting polymers of catechol-aminophenol/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.