One-pot synthesis of poly(3,4-Ethylenedioxythiophene)-Pt nanoparticle composite and its application to electrochemical H₂o₂ sensor

Poly(3,4-ethylenedioxythiophene)-Pt nanoparticle composite was synthesized in one-pot fashion using a photo-assisted chemical method, and its electrocatalytic properties toward hydrogen peroxide (H₂O₂) was investigated. Under UV irradiation, the rates of the oxidative polymerization of EDOT monomer along with the reduction of Pt⁴⁺ ions were accelerated. In addition, the morphology of PtNPs was also greatly influenced by the UV irradiation; the size of PtNPs was reduced under UV irradiation, which can be attributed to the faster nucleation rate. The immobilized PtNPs showed excellent electrocatalytic activities towards the electroreduction of hydrogen peroxide. The resultant amperometric sensor showed enhanced sensitivity for the detection of H₂O₂as compared to that without PtNPs, i.e., only with a layer of PEDOT. Amperometric determination of H₂O₂ at -0.55 V gave a limit of detection of 1.6 μM (S/N = 3) and a sensitivity of 19.29 mA cm^-2 M^-1 up to 6 μM, with a response time (steady state, t₉₅) of 30 to 40 s. Energy dispersive X-ray analysis, transmission electron microscopic image, cyclic voltammetry (CV), and scanning electron microscopic images were utilized to characterize the modified electrode. Sensing properties of the modified electrode were studied both by CV and amperometric analysis.