Fenton-like Reaction-Mediated Etching of Gold Nanorods for Visual Detection of Co2+

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• 作者：Zhiyang Zhang ; Zhaopeng Chen ; Dawei Pan ; Lingxin Chen
• 刊名：Langmuir
• 出版年：2015
• 出版时间：January 13, 2015
• 年：2015
• 卷：31
• 期：1
• 页码：643-650
• 全文大小：528K
• ISSN：1520-5827

文摘

We have proposed a Fenton-like reaction-mediated etching of gold nanorods and applied it to the sensitive visual detection of Co²⁺ ions. With the presence of bicarbonate (HCO₃^{鈥?/sup>) and hydrogen peroxide(H₂O₂), Co2+ ions trigger a Fenton-like reaction, resulting in the generation of superoxide radical (O₂鈥⑩€?/sup>). As a result, the gold nanorods are gradually etched by O₂鈥⑩€?/sup> in the presence of SCN鈥?/sup>, accompanied by an obvious color change from green to red. The gold nanorods etching process preferentially occurs along the longitudinal direction, which is observed by transmission electron microscope. The etching mechanism is carefully proved by investigating the effects of different radical scavengers (e.g., dimethyl sulfoxide). The auto-oxidation of hydroxylamine assay further confirms the mechanism. Then, the main factors, including reactants concentrations, temperature, and incubation time, are specifically investigated. Under optimized conditions, we get an excellent sensing performance for Co2+ with a lower detection limit of 1.0 nM via a spectrophotometer and a visual detection limit of 40 nM. In addition, this principle may provide a new concept of 鈥渋ntermediate-mediated etching of nanoparticles鈥?for sensing.}