Conducting polythiophene/α-Fe2O3 nanocomposite for efficient methanol electrochemical sensor

The combination of inorganic semiconductor metal oxides and organic conducting polymers is a favorable strategy in fabricating electrochemical sensors due to their outstanding electrocatalytic performance. Herein, a novel electrochemical sensor for detection of liquid methanol is fabricated using a modified glassy carbon electrode (GCE) with Nafion binder. The active sensing material is composed of a conductive polythiophene (PTh) doped iron oxide (alpha-Fe2O3) that simply synthesized by a facile sol-gel route in presence of a structure directing agent F127 followed by an oxidative polymerization process. Cyclic voltammetry and electrochemical impedance measurements revealed enhanced electrocatalytic response at the PTh/alpha-Fe2O3/Nafion modified GCE compared to either alpha-Fe2O3/GCE or bare GCE with a diffusion-controlled kinetics in ferro/ferricyanide redox couple. Material characterization using various analytical techniques confirmed the formation of PTh sheets onto highly crystalline rhombohedral structure of alpha-Fe2O3 with distinctly lattice fringes 0.37 nm. Outstanding sensing parameters are achieved with a sensor sensitivity of 0.793 mu AmM(-1)cm(-2), limit of detection LOD at (S/N = 3) = 1.59 mM, a wide range of methanol concentration from 5 to 1000 mM with a correlation coefficient R-2 = 0.9483. Furthermore, the current proposed sensor electrode showed adequate operational stability and acceptable reproducibility and repeatability.