title: One-pot green synthesis of oxygen-rich nitrogen-doped graphene quantum dots and their potential application in pH-sensitive photoluminescence and detection of mercury(II) ions.
abstract: Nitrogen doping has been a powerful method to modulate the properties of carbon materials for various applications, and N-doped graphene quantum dots (GQDs) have gained remarkable interest because of their unique chemical, electronic, and optical properties. Herein, we introduce a facile one-pot solid-phase synthesis strategy for N-doped GQDs using citric acid (CA) as the carbon source and 3,4-dihydroxy-L-phenylalanine (L-DOPA) as the N source. The as-prepared N-GQDs with oxygen-rich functional groups are uniform with an average diameter of 12.5 nm. Because of the introduction of nitrogen atoms, N-GQDs exhibit excitation-wavelength-independent fluorescence with the maximum emission at 445 nm, and a high quantum yield of 18% is achieved at an excitation wavelength of 346 nm. Furthermore, a highly efficient fluorosensor based on the as-prepared N-GQDs was developed for the detection of Hg(2+) because of the effective quenching effect of metal ions via nonradiative electron transfer. This fluorosensor exhibits high sensitivity toward Hg(2+) with a detection limit of 8.6 nM. The selectivity experiments reveal that the fluorescent sensor is specific for Hg(2+). Most importantly, the practical use of the sensor based on N-GQDs for Hg(2+) detection was successfully demonstrated in river-water samples.
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, China; Department of Chemistry and Life Sciences, Baise University, Baise, Guangxi 533000, China.
authors.forename: Bingfang
authors.initials: B
authors.lastname: Shi
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, China.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, China.
authors.forename: Chuanqing
authors.initials: C
authors.lastname: Lan
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, China.
authors.forename: Jingjin
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, China.
authors.forename: Yubin
authors.initials: Y
authors.lastname: Su
authors.affiliation: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education), College of Chemistry and Pharmacy, Guangxi Normal University, Guilin 541004, China. Electronic address: zhaoshulin001@163.com.
authors.forename: Shulin
authors.initials: S
authors.lastname: Zhao
mesh_terms: D019343:Citric Acid / Q000737:chemistry; D006108:Graphite / Q000737:chemistry / Q000528:radiation effects; D006863:Hydrogen-Ion Concentration; D007980:Levodopa / Q000737:chemistry; D049449:Luminescence; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry / Q000528:radiation effects; D010100:Oxygen / Q000737:chemistry / Q000528:radiation effects; D045663:Quantum Dots / Q000737:chemistry* / Q000528:radiation effects; D045483:Rivers / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D014874:Water Pollutants, Chemical; D019343:Citric Acid; D007980:Levodopa; D006108:Graphite; D008628:Mercury; D009584:Nitrogen; D010100:Oxygen
keywords: Fluorescence probe; Green synthesis; Mercury; Oxygen-rich nitrogen-doped graphene quantum dots; pH-Sensitive photoluminescence