Highly Photoluminescent and Stable N-Doped Carbon Dots as Nanoprobes for Hg2+ Detection

Longshi Rao; Yong Tang; Hanguang Lu; Shudong Yu; Xinrui Ding; Ke Xu; Zongtao Li; Jin Z Zhang

doi:10.3390/nano8110900

Highly Photoluminescent and Stable N-Doped Carbon Dots as Nanoprobes for Hg²⁺ Detection

Nanomaterials (Basel). 2018 Nov 2;8(11):900. doi: 10.3390/nano8110900.

Authors

Longshi Rao^{1

2}, Yong Tang³, Hanguang Lu⁴, Shudong Yu^{5

6}, Xinrui Ding⁷, Ke Xu^{8

9}, Zongtao Li¹⁰, Jin Z Zhang¹¹

Affiliations

¹ Engineering Research Centre of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China. memerls@mail.scut.edu.cn.
² Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA. memerls@mail.scut.edu.cn.
³ Engineering Research Centre of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China. ytang@scut.edu.cn.
⁴ Engineering Research Centre of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China. guyuexuan1999@foxmail.com.
⁵ Engineering Research Centre of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China. shudong.yu@partner.kit.edu.
⁶ Light Technology Institute, Karlsruhe Institute of Technology (KIT), Engesserstrasse 13, 76131 Karlsruhe, Germany. shudong.yu@partner.kit.edu.
⁷ Engineering Research Centre of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China. dingxr@scut.edu.cn.
⁸ Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA. kxu26@ucsc.edu.
⁹ Department of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China. kxu26@ucsc.edu.
¹⁰ Engineering Research Centre of Green Manufacturing for Energy-Saving and New-Energy Technology, School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China. meztli@scut.edu.cn.
¹¹ Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA. zhang@ucsc.edu.

Abstract

We developed a microreactor with porous copper fibers for synthesizing nitrogen-doped carbon dots (N-CDs) with a high stability and photoluminescence (PL) quantum yield (QY). By optimizing synthesis conditions, including the reaction temperature, flow rate, ethylenediamine dosage, and porosity of copper fibers, the N-CDs with a high PL QY of 73% were achieved. The PL QY of N-CDs was two times higher with copper fibers than without. The interrelations between the copper fibers with different porosities and the N-CDs were investigated using X-ray photoelectron spectroscopy (XPS) and Fourier Transform infrared spectroscopy (FTIR). The results demonstrate that the elemental contents and surface functional groups of N-CDs are significantly influenced by the porosity of copper fibers. The N-CDs can be used to effectively and selectively detect Hg²⁺ ions with a good linear response in the 0~50 μM Hg²⁺ ions concentration range, and the lowest limit of detection (LOD) is 2.54 nM, suggesting that the N-CDs have great potential for applications in the fields of environmental and hazard detection. Further studies reveal that the different d orbital energy levels of Hg²⁺ compared to those of other metal ions can affect the efficiency of electron transfer and thereby result in their different response in fluorescence quenching towards N-CDs.

Keywords: Hg2+ detection; carbon dots; microreactor; porous copper fibers.

Abstract

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