Two Electron Transfer Mediated Enhanced Electrochemical Nitrate Detection by Sn Doped CuxO Thin Film Electrode

Abstract

The unique electrochemical and electronic properties of CuxO (Cu2O/CuO) gives it merit to be used in the development of electronic devices. This paper presents the facile chemical route for the development of a sensitive, accurate, and low-cost nitrate electrochemical sensor based on undoped and Sn-doped CuxO thin film electrode. Various characterization techniques were used to study the physical, electro-chemical, and electronic properties of the material. Sn-doping resulted in an increase in the number of electron transfers from 1 to 2 as compared to undoped CuxO. The prepared sensor exhibited a high sensitivity of 100.27 µA mM-1cm-2, a wide linear concentration range of up to 50 mM, a fast response time of < 5 s was observed at a potential of -1 V (vs. Ag / AgCl), and a very low limit of detection of 0.04 µM (S/N = 3) that outperformed those in the recent literature. The electrode was selective for nitrate in the presence of common interference species and exhibited chemical stability and reproducibility.

Keywords: spin-coating, metal-organic decomposition, Sn-doping, Thin films, electrochemical sensor