Study on the interactions between graphene quantum dots and Hg(II): Unraveling the origin of photoluminescence quenching of graphene quantum dots by Hg(II)

Kappen, Jincymol; Ponkarpagam, S.; John, S. Abraham

doi:10.1016/j.colsurfa.2020.124551

Cited by 12 publications

(9 citation statements)

References 35 publications

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“…While looking into Figure S2, a dissolution peak was observed at +0.46 V, and it indicates that GQDs can reduce Hg(II) to Hg(0) even in the absence of Ag(0). 35 However, the dissolution current due to the GRR between Hg(II) and Ag-GQDs was 1.6-fold higher than that of Hg(II) reduction by GQDs under identical conditions. As discussed above, few oxygen functional groups remain on the surface of Ag-GQDs as evidenced from the emission spectra.…”

Section: ■ Results and Discussionmentioning

confidence: 94%

“…To find the role of GQDs, GC/GQDs were treated with Hg(II) and then DPV was recorded. While looking into Figure S2, a dissolution peak was observed at +0.46 V, and it indicates that GQDs can reduce Hg(II) to Hg(0) even in the absence of Ag(0) . However, the dissolution current due to the GRR between Hg(II) and Ag-GQDs was 1.6-fold higher than that of Hg(II) reduction by GQDs under identical conditions.…”

Section: Resultsmentioning

confidence: 96%

“…Figure B depicts the expanded spectrum of mercury on the GQD surface. The dominant peaks at 99.9 and 103.9 eV with a doublet splitting value of 4 eV imply the presence of Hg(0) on the GQD surface . Even though the available oxygen functional groups on the GQD surface are exhausted for the reduction of silver ions during the formation of Ag-GQDs, few oxygen functional groups are left out on the GQD surface as evidenced from the emission spectrum (Figure B).…”

Section: Resultsmentioning

confidence: 99%

“…The dominant peaks at 99.9 and 103.9 eV with a doublet splitting value of 4 eV imply the presence of Hg(0) on the GQD surface. 35 Even though the available oxygen functional groups on the GQD surface are exhausted for the reduction of silver ions during the formation of Ag-GQDs, few oxygen functional groups are left out on the GQD surface as evidenced from the emission spectrum (Figure 1B). These oxygen functionalities and electron-rich graphene moiety on the GQD surface can assist the reduction of Hg(II) in addition to GRR.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Unusual Reactivity of Graphene Quantum Dot-Wrapped Silver Nanoparticles with Hg(II): Spontaneous Growth of Hg Flowers and Their Electrocatalytic Activity

2021

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The galvanic reaction (GR) between a graphene quantum dot (GQD)-stabilized AgNP (Ag-GQD)-modified glassy carbon (GC) surface and Hg(II) leads to complete dissolution of AgNPs within 15 min and subsequent growth of Hg(0) as a “flower” on the GQD surface. This is unusual because generally the GR of bulk Ag/AgNPs with Hg(II) leads to the formation of a Hg–Ag amalgam/core shell structure. The appearance of peaks at 99.9 and 103.9 eV in X-ray photoelectron spectroscopy confirms Hg(0) on GQDs, whereas the disappearance of a peak at 370 eV indicates complete dissolution of Ag(0). When 200 ppm Hg(II) interacts with Ag-GQDs for 10 min, coalescence of AgNPs takes place along with the formation of Hg(0) petals separately. However, Hg(0) is grown as a flower with 2 μm size, and complete dissolution of AgNPs occurs subsequently after 15 min. The reason for anti-amalgamation is the direct deposition of Hg(0) by the available oxygen functional groups, followed by its strong adsorption on the graphene surface of GQDs. The subsequent growth of Hg(0) as a flower is due to the GR between AgNPs and Hg(II). Interestingly, the Hg flower-GQD-modified GC electrode acts as a good electrocatalyst toward H2O2 reduction by decreasing its overpotential by 150 mV in contrast to GC/Ag-GQDs.

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Section: ■ Results and Discussionmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

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Unusual Reactivity of Graphene Quantum Dot-Wrapped Silver Nanoparticles with Hg(II): Spontaneous Growth of Hg Flowers and Their Electrocatalytic Activity

2021

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“…For this, EDTA, a chelating agent with high affinity toward Hg 2+ ions, was introduced into the Mn-GQD-Hg (II) system. When EDTA is added to the solution that contains mercury salt and GQDs, owing to the higher complexation constant between EDTA and Hg, − Hg 2+ ions detach from the GQDs and chelate the Hg 2+ ions to form the EDTA–Hg complex. The removal of Hg 2+ from the GQDs leads to the disaggregation of Mn-LGQDs and finally restores PL.…”

Section: Resultsmentioning

confidence: 99%

In Situ Doping-Enabled Metal and Nonmetal Codoping in Graphene Quantum Dots: Synthesis and Application for Contaminant Sensing

Nair

Chava

Bose

et al. 2020

ACS Sustainable Chem. Eng.

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Fluorescent graphene quantum dots (GQDs) prepared from low-cost and sustainable precursors are highly desirable for various applications, including luminescence-based sensing, optoelectronics, and bioimaging. Among different natural precursors, the unique structural and compositional variety and the abundance of aromatic carbon in lignin make it a unique and renewable precursor for the green synthesis of advanced carbon-based materials including GQDs. However, the inferior photoluminescence quantum yield of GQDs prepared from natural precursors, including lignin, limits their practical utility. Here, for the first time, we demonstrate that the presence of heteroatoms in the innate structure of lignosulfonate can be leveraged to derive in situ heteroatom-doped GQDs with excellent photophysical properties. The as-synthesized lignosulfonate-derived GQDs showed compelling blue fluorescence with a high quantum yield of 23%, which is attributed to in situ S and N doping as confirmed by using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy analyses. Assisted by the in situ doping, we further engineered the lignosulfonate-derived GQDs by incorporating a metal atom dopant to derive an enhanced quantum yield of 31%, the highest for any lignin-derived GQDs. Moreover, fundamental photoluminescence studies reveal the presence of multiple emissive centers, with edge states acting as dominant emission centers. Finally, we also demonstrate the applicability of the luminescent, metal- and nonmetal-codoped lignin-derived GQDs as a highly selective sensor for the sub-nanomolar level detection of mercuric ions in water.

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Fluorescent dendritic fibrous nanosilica/polyurethane composite membranes for selective and sensitive recognition and removal of Hg2+/Hg+ ions

He,

Zhang,

Cheng

2023

Chemical Engineering Journal

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Study on the interactions between graphene quantum dots and Hg(II): Unraveling the origin of photoluminescence quenching of graphene quantum dots by Hg(II)

Cited by 12 publications

References 35 publications

Unusual Reactivity of Graphene Quantum Dot-Wrapped Silver Nanoparticles with Hg(II): Spontaneous Growth of Hg Flowers and Their Electrocatalytic Activity

Unusual Reactivity of Graphene Quantum Dot-Wrapped Silver Nanoparticles with Hg(II): Spontaneous Growth of Hg Flowers and Their Electrocatalytic Activity

In Situ Doping-Enabled Metal and Nonmetal Codoping in Graphene Quantum Dots: Synthesis and Application for Contaminant Sensing

Fluorescent dendritic fibrous nanosilica/polyurethane composite membranes for selective and sensitive recognition and removal of Hg2+/Hg+ ions

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