Electrochemical Synthesis of Poly(3,4-ethylenedioxythiophene) and Gold Nanocomposite and Its Application for Hypochlorite Sensor

The AuNPs/PEDOT nanocomposite consisting of poly(3,4-ethylendioxythiophene) and Au nanoparticles (AuNPs) can be easily synthesized on electrode surface. It was studied to develop a new NaClO sensor with improved performance with respect to bare electrode and to pure metallic (AuNPs) modified electrodes. This nanocomposite can be performed by electrochemical co-deposition using ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMT). It was further characterized by surface-confined and linear pH-dependence (-60 mV pH -1 ) in the electrochemical system. AuNPs/PEDOT exhibits grain-like structure and the significant average diameter between PEDOT and AuNPs, which is due to AuNPs covered over PEDOT surface. The composite of AuNPs/PEDOT was analyzed by XRD and the AuNPs fraction was estimated in 60.29 wt%. The significant electron transfer resistance (Ret) is found between PEDOT and AuNPs due to it maintains the partial property of PEDOT and AuNPs. It also exhibits good sensitivity of 208.8 mA M -1 cm -1 (S/N = 3), detection limit of 1 μM, and linear range of 10 -6 –9.32×10 -4 M (correlation coefficient, R 2 = 0.9975) for hypochlorite detection. Moreover, the proposed nanocomposite is suitable to be a hypochlorite sensor and found no interference even in the presence of hydrogen peroxide and ethanol.