Mechanism research of SDBS-functionalized polypyrrole to improve electrochemical performance of screen-printed graphene electrode

Abstract

A novel method to enhance the response sensitivity of screen-printed graphene electrode (SPGE) by modifying functionalized polypyrrole (PPy) is proposed. Functionalized PPy was synthesized at low temperature by doping sodium dodecyl benzene sulfonate (SDBS) using a non-covalent modification technique, and then modified on the surface of SPGE. Due to the introduction of hydrophilic heads dodecyl benzene sulfonate (DBS−), SDBS-functionalized polypyrrole exhibited a larger specific surface area and high dispersion. The structure and morphology of SDBS-functionalized polypyrrole were characterized by X-ray diffraction and scanning electron microscopy. The electrochemical behavior of SDBS-functionalized polypyrrole-modified SPGE (SDBS/PPy-SPGE) was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) of potassium ferricyanide (K3[Fe(CN)6]). Compared with bare SPGE, the anodic currents sensitivity of SDBS/PPy-SPGE was improved from 11.38 μA·mM−1 to 15.17 μA·mM−1, and the oxidation current was increased by 78.06% in measuring 1 mM K3[Fe(CN)6] (PF). The adsorption energy and electron transfer of pure PPy and SDBS/PPy to PF molecules were calculated based on density functional theory (DFT). The adsorption energy (from -0.41 eV to -1.11 eV) and electron transfer (from 0.4 e to 0.56 e) of SDBS/PPy to PF molecules were significantly enhanced. These can be attribute to the large specific surface area, high dispersibility and chemical stability of PPy upon being non-covalently functionalized by SDBS. The electrochemical sensitivity and stability of SPGE was greatly enhanced by the synergistic effect of graphene and SDBS/PPy. Thus, SDBS-functionalized polypyrrole is a promising material for improving the electrochemical properties of electrode.