A highly sensitive persulfate sensor based on a hybrid nanocomposite with silicomolybdate doping poly(3,4-ethylenedioxythiophene) on multi-walled carbon nanotubes

A novel hybrid nanocomposite has been successfully fabricated for persulfate (S2O82-) detection. It can be easily prepared by grafting silicomolybdate (SiMO) and poly(3,4-ethylenedioxythiophene) (PEDOT) on multi-walled carbon nanotubes (MWCNT) to form a SiMO-PEDOT/MWCNT hybrid composite. The SiMO-PEDOT film formation is initiated through the electropolymerization of EDOT monomers. The monomers are firstly electropolymerized to form the positive PEDOT and then the positive polymers are attractive to the negative SiMO, resulting in the electrocodeposition on the electrode surface. It shows three significant redox couples and the redox peak currents can be enhanced by using a MWCNT-modified electrode. Morphological features were studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The electrode shows good activity towards S2O82- reduction with low overpotential (E-pc = 0 V). Amperometric response provides a linear range of 1-3333 M with sensitivity of 2928.9 mu A mM(-1) cm(-2), a detection limit of 1 x 10(-6) M (S/N = 3), and response time of 2.3 s. The SiMO-PEDOT/MWCNT electrode can effectively analyse S2O82- due to its low overpotential, high sensitivity, good stability, fast response, and low cost.