Preparation And Analytical Application Of Bismuth And Antimony Electrode

A copper-based Cu-Bi(Sb)/Bi(Sb) composite film, which is consisted of a copper-bismuth/antimony alloy transitional layer and an outer layer electrodeposited bismuth/antimony film, was prepared on a copper substrate. The prepared composite film electrode exhibits low cost, easy fabrication, long term stability, low toxicity. The purpose of our work is to propose a methodology to fabricate a copper-based Cu-Bi(Sb)/Bi(Sb) composite film. The analytical application of the electrode was also estimated. Three main aspects were included in the dissertation:1. The electrode was firstly prepared by cyclic voltammetry to get a copper-bismuth alloy layer on the surface of a copper substrate. Then a bismuth film was plated on the alloy layer by electrolytic deposition in the electrolyte containing bismuth(III). The characteristics of the bismuth film was investigated with X-Ray diffraction, X-ray photoelectron spectroscopy and electrochemicalmethods. That the pre-treatment processes of the inert substrate electrode (including polishing and cleaning), do not enable the conditions of the electrode surface uniform each other. Therefore the homogeneity and the thickness of the plated bismuth film are not identical for every electrode. Due to formation of a transitional alloy layer, the robustness and reproducibility of the composite bismuth film were enhanced tremendously. For the purpose of improving the morphology and structure of the bismuth film, the stabilizer EDTA, lubricant PEG and brightener p-toluene sulfonamide were added into electrolyte. The factors of electro-deposition and the operation parameters were completely investigated in terms of their influence on the SWASV signals. It is clear that the sensitivity of this composite bismuth film is much lower than not only the mercury film also the inert metal-based bismuth film. This is mainly attributed to the very thicker bismuth film (ca. 300 nm). Although the sensitivity of the composite bismuth film electrode is not satisfied, but is good enough for use in polluted water monitoring. Low cost, easy fabrication, stable adherence, low toxicity, good linearity and reproducibility and long term usage stability, all of these enable it a practical use in the on-site monitoring.2. Also, we use the same electrochemical method to get a copper-based Cu-Sb/Sb composite film. Firstly a transitional Cu-Sb alloy layer was formed on the copper electrode surface by cyclic voltammetry, the antimony film then was plated on the alloy layer by potentiostatic technique. The characteristics of the antimony film was investigated with scanning electron microcopy, X-ray photoelectron spectroscopy and electrochemical methods. The sensitivity of the composite antimony film is higher than the composite bismuth film. The composite film electrode displayed an excellent linear behavior in the detection of Cd(II) and Pb(II) with the concentration range from 1 to 5μgL^-1(R²=0.987 for Cd(II) and 0.999 for Pb(II)), 6 to 10μgL^-1(R²=0.995 for Cd(II) and 0.999 for Pb(II)), 10 to 100μgL^-1(R²=0.991 for Cd(II) and 0.999 for Pb(II)). The detection limit of the composite bismuth film electrode was estimated to be 0.25μg/L and 0.08μg/L for Cd(II) and Pb(II) respectively. The repetitive measurements yielded a relative standard deviation (RSD) of±2.8% for Cd(II) and±5.6% for Pb(II) (50μgL^-1, n=7). In short, the antimony electrode exhibits good application value.3. In addition, a antimony/bismuth alloy film electrode has been fabricated by electrochemically reduction on the glassy carbon electrode or copper electrode. Until now, nobody has been use the antimony/bismuth alloy film electrode. Considering the mercury electrode can substitute by antimony or bismuth, we have the idea to use the both of antimony and bismuth. Finally we get some useful data in the paper.