Adsorption of aniline on silver mirror studied by surface‐enhanced Raman scattering spectroscopy and density functional theory calculations

Qi, Yajing; Hu, Yongjun; Xie, Min; Xing, Da; Gu, Hui

doi:10.1002/jrs.2864

Cited by 47 publications

(34 citation statements)

References 51 publications

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“…Moreover, the CT mechanism depends sensitively on the particular chemical bonds between the analyte and the substrate, resulting in shifts in peak positions. 14 As shown in Fig. S2 (ESI †), the SERS intensity of As(V) was proportional to the excitation wavelength.…”

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confidence: 86%

Rapid in situ identification of arsenic species using a portable Fe₃O₄@Ag SERS sensor

Cui

Jing

2014

Chem. Commun.

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Rapid and sensitive SERS identification and quantification of arsenic species in multiple matrices have been realized using a Fe 3 O 4 @Ag magnetic substrate. The molecular structure of arsenic on Fe 3 O 4 @Ag characterized using EXAFS spectroscopy and DFT confirms the existence of a chemical effect on SERS enhancement.Arsenic (As) contamination is a pressing environmental issue that causes serious threat to human health. 1 The presence of As has been well documented in multiple environmental matrices including groundwater, soil and sediment, and foods. 2 The toxicity and mobility of As depend on its oxidation state, where arsenite (As(III)) is 50-100 times more toxic than arsenate (As(V)). 1 As speciation analysis is usually achieved by separation using high performance liquid chromatography combined with mass spectrometry or atomic absorption/ fluorescence spectrometry. These techniques require samples to be collected and transported to the laboratory, which may induce As(III) oxidation, and thus lead to biased conclusions on its toxicity. Therefore, the need for rapid and sensitive field As speciation analysis has motivated great research efforts for decades. 3 Recently, As field testing kits were developed, but failed in a high fraction of cases when analyzing groundwater samples. 4,5 Nevertheless, most current field detection methods are not capable of As speciation analysis. 6 Surface enhanced Raman scattering (SERS) spectroscopy provides an alternative tool for fast screening of As-contaminated environmental samples. Previous studies proved that silver (Ag) substrates can achieve SERS sensing of 10 mg L À1 As(III) and As(V). 6-9 However, the Ag SERS substrate was susceptible to matrix effects, and could not even detect 10 mg L À1 As(V) in a spiked groundwater sample. 10 Therefore, either complicated pretreatment or a standard addition method is needed to compensate for the reduced SERS sensitivity in real environmental matrices. 6,10 The lack of reliable in situ methodology has prevented wide application of the SERS technique. Herein, we present a portable SERS sensor for onsite monitoring of arsenic speciation. Fe 3 O 4 @Ag core-shell magnetic NPs, which are capable of fast preconcentration, rapid separation, and exhibit high SERS sensitivity, were used as reliable SERS substrates for determination of As(III) and As(V). The entire process can be completed within 2 min. Moreover, the active SERS substrate can be used for As sensing in complex media such as juice, wine, and soils.The detailed synthetic procedure for Fe 3 O 4 @Ag NPs is described in the ESI. † The morphology and structure of Fe 3 O 4 @Ag were characterized by transmission electron microscopy (TEM) and high-resolution (HR) TEM. A 10 nm Ag layer was coated on the 70 AE 20 nm Fe 3 O 4

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confidence: 86%

Rapid in situ identification of arsenic species using a portable Fe₃O₄@Ag SERS sensor

Cui

Jing

2014

Chem. Commun.

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“…The cluster model, in conjunction with DFT calculation, was employed for the characterization of a variety of molecule-metal cluster complex systems and to predict their excitation energies and SERS spectra [20][21][22][23][24] . It has also been proposed that silver clusters, with different number of atoms, can be used to simulate the silver nanoparticle to which the organic molecule is adsorbed 19,20,25 .…”

Section: Introductionmentioning

confidence: 99%

SERS Spectra of Alizarin Anion–Ag_n (n = 2, 4, 14) Systems: TDDFT Calculation and Comparison with Experiment

et al. 2016

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Using density functional theory (DFT) and various cluster models for the simulation of the interaction between alizarin and silver nanoparticles, we calculated the SERS spectra of the AZ anion-Ag n (n=2, 4, 14) complexes and compared the results with experiment. The analysis of the calculated SERS spectra helped distinguishing the contribution of the chemical and electromagnetic mechanisms to the spectral enhancement, under the assumption that the excitation energies of the clusters are comparable with the local plasmon energies of nanoparticles. The results show a certain dependence of the relative Raman intensities and peak positions on the silver cluster size. Calculation of UV-VIS transition energies and Raman spectra of the complexes have been performed under the assumption that the AZ anion is bounded to the silver clusters through the oxygen atoms of the C=O groups in 1,9 positions, in a edge-on perpendicular orientation. The calculated SERS spectra show an acceptable similarity with the experimental SERS spectra carried out with excitation at 632 nm. The results of the calculation under pre-resonance condition with respect to chromophore located and cluster located excitations are compatible with mechanisms of enhancement acting on different parts of the AZ anion molecule. The calculations were performed using the B3LYP hybrid density functional. A 6-31g(d) basis set for H, C, O and LANL2DZ basis set for Ag were used. Vertical excitation energies and the corresponding oscillator strengths were calculated by means of time dependent density functional theory (TDDFT).

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“…Several research groups have studied the adsorption mechanisms of molecules on SERS active substrates employing both theoretical calculations and Raman scattering experiments. Qi et al . combined SERS spectroscopy and density functional theory (DFT) calculations for studying adsorption of aniline on a silver mirror surface.…”

Section: Introductionmentioning

confidence: 99%

Silver‐capped silicon nanopillar platforms for adsorption studies of folic acid using surface enhanced Raman spectroscopy and density functional theory

Castillo

Rindzevicius

et al. 2015

J Raman Spectroscopy

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The study of the interactions of folic acid (FA) with surface enhanced Raman scattering substrates is relevant for understanding its adsorption mechanism and for fabricating analytical devices for detection of malignant cells over‐expressing folate receptors. This paper presents a study of the adsorption of FA on silver‐capped silicon nanopillar substrates employing surface enhanced Raman scattering spectroscopy and density functional theory calculations. The experimentally observed vibrations from free FA and FA bound to the Ag surface display different vibrational spectra indicating chemical interaction of the molecule with the metal surface. Density functional theory calculations show that the Ag–FA interaction is primarily through the nitrogen from the pteridine ring anchoring to the Ag metal surface. To investigate the Ag–FA binding behavior further, the adsorption isotherm of FA on the silver‐capped silicon nanopillar surface is estimated. The results show a positive cooperative Ag–FA binding mechanism. That is, adsorbed FA increases the affinity of new incoming FA molecules. Copyright © 2015 John Wiley & Sons, Ltd.

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Adsorption of aniline on silver mirror studied by surface‐enhanced Raman scattering spectroscopy and density functional theory calculations

Cited by 47 publications

References 51 publications

Rapid in situ identification of arsenic species using a portable Fe₃O₄@Ag SERS sensor

Rapid in situ identification of arsenic species using a portable Fe₃O₄@Ag SERS sensor

SERS Spectra of Alizarin Anion–Ag_n (n = 2, 4, 14) Systems: TDDFT Calculation and Comparison with Experiment

Silver‐capped silicon nanopillar platforms for adsorption studies of folic acid using surface enhanced Raman spectroscopy and density functional theory

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Adsorption of aniline on silver mirror studied by surface‐enhanced Raman scattering spectroscopy and density functional theory calculations

Cited by 47 publications

References 51 publications

Rapid in situ identification of arsenic species using a portable Fe3O4@Ag SERS sensor

Rapid in situ identification of arsenic species using a portable Fe3O4@Ag SERS sensor

SERS Spectra of Alizarin Anion–Agn (n = 2, 4, 14) Systems: TDDFT Calculation and Comparison with Experiment

Silver‐capped silicon nanopillar platforms for adsorption studies of folic acid using surface enhanced Raman spectroscopy and density functional theory

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Rapid in situ identification of arsenic species using a portable Fe₃O₄@Ag SERS sensor

Rapid in situ identification of arsenic species using a portable Fe₃O₄@Ag SERS sensor

SERS Spectra of Alizarin Anion–Ag_n (n = 2, 4, 14) Systems: TDDFT Calculation and Comparison with Experiment