Herein, we demonstrated synthesis and application of silver nanoparticles (Ag-NPs) decorated nitrogen doped single-walled carbon nanotube through a one-step thermal-reduction method using melamine as the nitrogen source. Field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR) and X-ray diffraction data confirmed the successful synthesis of Ag-NPs functionalized nitrogen doped single-walled carbon nanotubes(Ag-N-SWCNTs). The nitrogen-doping notably modified the properties of the SWCNT and it showed stronger affinity for the attachment of Ag-NPs. By integrating the high surface area and electrical properties of N-SWCNTs with Ag-NPs, the obtained Ag-N-SWCNTs nanocomposite showed high catalytic activity than N-SWCNTs and pristine-SWCNTs. The enzyme-based methods have some disadvantages. For example, high fabrication cost and poor stability, due to these intrinsic disadvantages, non-enzymatic sensors have received more interest in fabrication of sensors. A non-enzymatic electrochemical urea sensor was developed by modifying glassy carbon electrode (GCE) with Ag-N-SWCNTs and a layer of Nafion (Nf). Thus, the fabricated sensor exhibited lower limit of detection (4.7 nM), with an enhanced sensitivity of 141 μAmM⁻¹cm⁻² for urea detection in the range of 66 nM to 20.6 mM(R² = 0.966). The reliability of the as-fabricated sensor was successfully investigated by using it to detect urea in tap water and milk samples. The NF/Ag-N-SWCNTs based urea sensor offers several advantages such as simple fabrication procedure, non-enzymatic and low-cost, so this sensor can be applied to detect urea in various samples from food, fertilizer industries and environmental fields. Moreover, the modified electrode showed phenomenal stability with no loss in activity of storage under ambient conditions. In addition, the novel hybrid NF/Ag-N-SWCNTs/GCE showed high selectivity toward urea with good repeatability and reproducibility further confirmed that this method can be utilized for detection of urea.

中文翻译：

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银纳米颗粒锚固氮掺杂单壁碳纳米管修饰电极上尿素的非酶电化学检测

在这里，我们证明了通过使用三聚氰胺作为氮源的一步热还原法，银纳米颗粒（Ag-NPs）装饰的氮掺杂单壁碳纳米管的合成和应用。场发射扫描电子显微镜（FE-SEM），傅立叶变换红外光谱（FT-IR）和X射线衍射数据证实了Ag-NPs功能化氮掺杂单壁碳纳米管（Ag-N-SWCNTs）的成功合成）。氮掺杂显着改变了SWCNT的性能，并且对Ag-NP的附着表现出更强的亲和力。通过将N-SWCNTs的高表面积和电性能与Ag-NPs相结合，所获得的Ag-N-SWCNTs纳米复合材料比N-SWCNTs和原始SWCNTs具有更高的催化活性。基于酶的方法具有一些缺点。例如，由于这些固有的缺点，高制造成本和较差的稳定性使非酶传感器对传感器的制造越来越感兴趣。通过使用Ag-N-SWCNT和一层Nafion（Nf）修饰玻璃碳电极（GCE），开发了一种非酶促电化学尿素传感器。因此，制成的传感器显示出较低的检测下限（4.7 nM），灵敏度提高了141μAmM用于尿素检测的^-1 cm ^-2在66 nM至20.6 mM（R ² = 0.966）的范围内。通过使用这种传感器检测自来水和牛奶样品中的尿素，成功地研究了其可靠性。基于NF / Ag-N-SWCNTs的尿素传感器具有一些优点，例如制造过程简单，无酶和低成本，因此该传感器可用于检测食品，化肥行业和环境领域的各种样品中的尿素。而且，修饰的电极表现出惊人的稳定性，在环境条件下没有失去储​​存活性。此外，新型杂种NF / Ag-N-SWCNTs / GCE对尿素的选择性高，重复性和重现性更好，进一步证实了该方法可用于尿素的检测。