Fabrication of high dispersion Pd/MWNTs nanocomposite and its electrocatalytic performance for bromate determination

Pd nanoparticles decorated multiwall carbon nanotubes (Pd/MWNTs) catalyst was synthesized by in situ chemical method and its application for the determination of bromate was investigated. The morphology and composition of the Pd/MWNTs catalyst was characterized by Transmission electron microscopy (TEM). Energy dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The analyses indicate that Pd nanoparticles in metallic-state were homogeneously deposited on MWNTs with an average diameter of 4.5 nm. The electrocatalytic activity of Pd/MWNTs for the reduction of bromate was investigated by cyclic voltammetry (CV). An obvious peak corresponding to the bromate reduction was obtained between 0.15 and -0.25 V. Effects of different factors including scan rate, temperature and initial concentration of bromate ions on bromate determination were studied as well. A good linear relationship between the values of reduction peak and bromate concentration was obtained. Chronoamperometric measurement showed that the Pd/MWNTs modified electrode could be successfully employed as an amperometric sensor for bromate in a wide concentration range (0.1-40 mM) within a short response time (5 s), and the sensitivity of this sensor is 768.08 mu A mM(-1) cm(-2). The results reported herein indicate that the Pd/MWNTs have a potential application in fabrication of bromate detector. (C) 2012 Elsevier B.V. All rights reserved.