title: Carbon quantum dots prepared with polyethyleneimine as both reducing agent and stabilizer for synthesis of Ag/CQDs composite for Hg2+ions detection.
abstract: A stable silver nanoparticles/carbon quantum dots (Ag/CQDs) composite was prepared by using CQDs as reducing and stabilizing agent. The CQDs synthesized with polyethyleneimine (PEI) showed an extraordinary reducibility. When Hg2+was presented in the Ag/CQDs composite solution, a color change from yellow to colorless was observed, accompanied by a shift of surface plasmon resonance (SPR) band and decrease in absorbance of the Ag/CQDs composite. On the basis of the further studies on TEM, XPS and XRD analysis, the possible mechanism is attributed to the formation of a silver-mercury amalgam. Hence, a two dimensional sensing platform for Hg2+detection was constructed upon the Ag/CQDs composite. Based on the change of absorbance, a good linear relationship was obtained from 0.5 to 50μM for Hg2+. And the limit of detection for Hg2+was as low as 85nM, representing high sensitivity to Hg2+. More importantly, the proposed method also exhibits a good selectivity toward Hg2+over other metal ions. Besides, this strategy demonstrates practicability for the detection of Hg2+in real water samples with satisfactory results.
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China.
authors: Ting
authors: T
authors: Liu
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China.
authors: Jiang Xue
authors: JX
authors: Dong
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China.
authors: Shi Gang
authors: SG
authors: Liu
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China.
authors: Na
authors: N
authors: Li
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China.
authors: Shu Min
authors: SM
authors: Lin
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China.
authors: Yu Zhu
authors: YZ
authors: Fan
authors: School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, PR China.
authors: Jing Lie
authors: JL
authors: Lei
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China. Electronic address: luohq@swu.edu.cn.
authors: Hong Qun
authors: HQ
authors: Luo
authors: Key Laboratory of Eco-environments in Three Gorges Reservoir Region (Ministry of Education), School of Chemistry and Chemical Engineering, Southwest University, No.2 Tiansheng Road, BeiBei District, Chongqing 400715, PR China. Electronic address: linb@swu.edu.cn.
authors: Nian Bing
authors: NB
authors: Li
keywords: Carbon quantum dots; Hg(2+); Polyethyleneimine; Silver nanoparticles; Surface plasmon resonance