Preparation, characterization and electrocatalytic studies on hybrid films of electropolymerized manganese tetra(o-aminophenyl)porphyrin and adsorbed flavins

Hybrid films composed of electropolymerized manganese tetra(o-aminophenyl)porphyrin (MnTAPP) and flavin adenine dinucleotide (FAD), or flavin mononucleotide (FMN), or riboflavin (RF) adsorbed film modified electrodes have been prepared from aqueous acidic solutions. The hybrid films showed four redox couples. Electrochemical quartz crystal microbalance combined with cyclic voltammetry was used to study the in situ growth of poly(MnTAPP) film as well as poly(MnTAPP)/FAD hybrid film. The stability of the adsorbed flavins molecules increased in the presence of poly(MnTAPP) film. Hybrid films have shown surface confined electron transfer characteristics and the peak potentials of redox couples are pH dependent. The electrocatalytic behavior of poly(MnTAPP)/Flavin hybrid films toward reduction of oxygen, NAD+, nitrite and S2O82- was investigated. Oxygen reduced at lesser potential on hybrid film compared to unmodified electrode. The electrocatalytic activity of hybrid films showed the order poly(MnTAPP)/FAD > poly(MnTAPP)/FMN > poly(MnTAPP)/RF toward reduction of NAD+ and NO2-.