Electrocatalytic nanocauliflower structured fluorine doped CdO thin film as a potential arsenic sensor

Abstract

Arsenic in water is considered as a global problem affecting human health as well as world’s economy. Intake of toxic arsenic leads to cytological effects leading to cancer and disorders such as black foot disease, hypertension and dermatitis. A low—cost spray deposited nanocauliflower like fluorine doped cadmium oxide (F-doped CdO) thin film based working electrode was developed to detect arsenic with lower detection limit. The structural properties of F-doped CdO thin film exhibited face centered cubic structure with high crystallinity. Morphological characterization of F-doped CdO highlighted the cauliflower like building blocks. F-doped CdO thin film showed a resistivity, sheet concentration and mobility of 0.13Ωcm, 8.18×1012cm−2 and 3151cm2V−1s−1 respectively. F-doped CdO showed a redox peak at −0.10 and 0.05V (vs Ag/AgCl) respectively without the use of arsenite oxidase or arsenate reductase enzymes and mediators. The redox reaction of arsenic was due to the inherent catalytic behaviour of F-doped CdO. The electrocatalytic activity of F-doped CdO helped in detecting arsenic with a detection limit of 4.55×10−3ppb and a sensitivity of 5.747×10−3μAppb−1. This suggests, F-doped CdO electrocatalyst can replace electrodes such as platinum, gold and glassy carbon electrodes and can be operated at wider potential ranges.