Sensing nitrite with a glassy carbon electrode modified with a three-dimensional network consisting of Ni₇S₆ and multi-walled carbon nanotubes

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• 作者：Wenqin Wu ; Yibin Li ; Jiayi Jin ; Huimin Wu ; Shengfu Wang ; Yu Ding…
• 关键词：Nanomaterial ; Cyclic voltammetry ; Linear sweep voltammetry ; Chronoamperometry ; Water analysis
• 刊名：Microchimica Acta
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：183
• 期：12
• 页码：3159-3166
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Nanochemistry; Nanotechnology; Characterization and Evaluation of Materials; Analytical Chemistry; Microengineering;
• 出版者：Springer Vienna
• ISSN：1436-5073
• 卷排序：183

文摘

We describe an amperometric sensor for nitrite that is based on a glassy carbon electrode modified with a 3-dimensional network consisting of Ni₇S₆ and multi-walled carbon nanotubes. The nickel sulfide was prepared by a hydrothermal method starting from nickel chloride and thiourea. The morphology and catalytic properties of the sensor material were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, cyclic and linear sweep voltammetry, electrochemical impedance spectroscopy, and chronoamperometry. The results showed the Ni₇S₆/MWCNTs to possess improved catalytic activity towards the oxidation of nitrite when compared to plain Ni₇S₆. The sensor is best operated at 0.425 V (vs. Ag/AgCl) in 0.1 M NaOH solution where it shows a linear response in the 1.0 μM to 4.2 mM nitrite concentration range, with a sensitivity as high as 185.0 μA·mM−1·cm−2 and a 0.3 μM detection limit (at a signal-to-noise ratio of 3). These features are mainly attributed to the large specific surface area of Ni₇S₆, the good electrical conductivity of the MWCNTs, and the synergy between Ni₇S₆ and the MWCNTs. The method was applied to the determination of nitrite in (spiked) water samples where it gave recoveries that ranged between 98.6 and 100.1 %.