Overoxidized Pedot-Ppy Composite Films with Improved Electrocatalytic Ability for Rutin and Luteolin

Abstract

In this study, a simple and effective method is proposed to improve the electrocatalytic activity of overoxidized poly(3,4-ethylenedioxythiophene)-polypyrrole (oPEDOT-oPPy) composite films for rutin and luteolin determination. The PEDOT-PPy / glassy carbon electrode (GCE) is prepared by cyclic voltammetry (CV) copolymerization under different potentials ranges with LiClO 4 -water as the supporting electrolyte. When the positive terminal potential is greater than 1.5 V, the prepared oPEDOT-oPPy/GCE after incubation in NaOH-EtOH solution with a volume ratio of 1:1 exhibits larger effective specific surface area ( A ), higher electron transfer rate constant ( k s ), and enhanced electrocatalytic performance for rutin and luteolin. The X-ray photoelectron spectroscopy (XPS) results indicate that the contents of -SO 2 /-SO and -C=N- structure in the composite films increase significantly after incubation. Further, the Raman and Fourier transform infrared spectra (FTIR) reveal that after incubation, the thiophene ring structure changes from benzene-type to quinone-type, a quinone-type pyrrole structure is formed, and the conjugated effect of the benzene-type pyrrole ring is enhanced. Based on density functional theory (DFT) calculations, it is verified that after incubation, the proposed oPEDOT and oPPy hexamer structure in the composite films exhibits enhanced electron-accepting ability, smaller energy gap ( E g ), and higher adsorption energy ( ΔE ad ) for luteolin, thereby improving the conductivity and adsorption ability of the composite films. Therefore, incubation plays a key role in improving the electrocatalytic performance of oPEDOT-oPPy composite films. Further, the synergistic effect of oPEDOT and oPPy causes the enhancement of the electrocatalytic ability of oPEDOT-oPPy composite films for rutin and luteolin determination.

Keywords: Overoxidized poly(3, 4-ethylenedioxythiophene)； Overoxidized polypyrrole；Incubation； Electrocatalytic ability