ZnO-nanoparticle Coated Multiwall Carbon Nanotube as a New Sensing Element for Highly Sensitive Potentiometric Determination of Thiosulfate Ion

Abstract

ZnO-nanoparticle Coated Multiwall Carbon Nanotube as a New Sensing Element for Highly Sensitive Potentiometric Determination of Thiosulfate Ion Here, we are reporting the response properties of a simple and useful potentiometric thiosulfate-selective electrode based on multiwall carbon nanotubes (MWCNTs) decorated with ZnO nanoparticles as sensing element. We successfully decorated the MWCNTs by using sol-gel process, which has not been reported to prepare such a decoration before. The ZnO-MWCNTs were characterized by XRD, SEM and TEM techniques. After optimization the composition requirements for construction the best electrode, the potentiometric response characteristics of the electrochemical sensor was examined for determination of thiosulfateanion in aqueous solutions. A Nernstian response of 30.3 ± 0.1 mV/dec with a detection limit of 1.24×10-7 M, a linear dynamic range of 1.35×10-7 to 1.45×10-1 M of thiosulfate and a response time of about 3 min are of good performance factors for the proposed electrode. The electrode demonstrated a reasonable repeatability and high selectivity towards the thiosulfate ion over the other tested anions in the solution.