PEDOT-Type Conducting Polymers/Black TiO2 Composites for Electrochemical Determination of Cd2+ and Pb2+

Abstract

In this paper, the PEDOT-type conducting polymers/black TiO2 composites were prepared by in situ polymerization method by varying the weight ratio of black TiO2 to monomer (3,4-ethylenedixoythiophene(EDOT) or 3,4-propylenedixoythiophene (ProDOT)). And, these composites (PEDOT/B-TiO2 and PProDOT/B-TiO2) were applied for the electrochemical determination of Cd2+ and Pb2+ by using differential pulse voltammetry (DPV). The relationship between the structure and electrochemical performances was studied systematically. The structural analysis revealed that the PEDOT-type conducting polymers could act with B-TiO2 by non-covalent bonding. The combination of polymers with B-TiO2 effectively enhanced adsorption and charge transfer ability of composites to heavy metal ions, which was favorable for enhancing the eletrcocatalytic ability of composites. The results showed that under optimized conditions, the limit of detection (LOD) of the PEDOT/B-TiO2 composite electrode from 50 wt% B-TiO2 are 0.00073 μM and 0.0816 μM, respectively, and the linear range of simultaneous detection of Pb2+ and Cd2+ is from 0.04 to 1.24 μM. In the case of PProDOT/B-TiO2, the LOD of composite electrode from 50 wt% B-TiO2 for Pb2+ are 0.00087 μM (0.04–0.4 μM) and 0.00186 μM (0.4–1.8 μM), respectively, and the LOD for Cd2+ are 0.01523 (linear range of 0.04–0.4 μM) and 0.03214 (linear range of 0.4–1.8 μM), respectively.