An investigation of the adsorption of pyrazine and pyridine on nickel electrodes by in situ surface-enhanced Raman spectroscopy

Huang, Qing‐An; Lin, Xiuzhu; Yang, Zhilin; Hu, J.W; Zhang, Tian

doi:10.1016/j.jelechem.2003.08.015

Cited by 41 publications

(16 citation statements)

References 81 publications

(113 reference statements)

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“…Hence the SERS signal of the v 6a mode depends on the applied potential in an electrochemical interface. 33 In this case, the displacement of the mode will increase and favor in the CT enhancement. …”

Section: Charge-transfer Enhancementmentioning

confidence: 99%

Density functional theory study of surface‐enhanced Raman scattering spectra of pyridine adsorbed on noble and transition metal surfaces

Duan

Ren

et al. 2005

J Raman Spectroscopy

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Pyridine as a typical model molecule has been most extensively studied by SERS for three decades. However, there has not been a satisfactory explanation for the dramatic change of the relative intensity of the two main bands assigned to the total symmetric modes at 1008 and 1035 cm(-1) when pyridine was adsorbed on silver and many other metals. We performed a hybrid density functional theory study of the binding interaction and the Raman spectral properties of pyridine-metal clusters. The calculated Raman scattering factors of total symmetric modes for the pyridine-metal complexes indicate that the bonding interaction influences the relative Raman intensity of the vibrational modes. The surface bonding mechanism was analyzed on the basis of molecular orbital theory. It was also shown that the binding interaction will lead to geometric changes and result in metal-dependent surface Raman spectra. This theoretical approach could be helpful in using SERS to study surface chemistry, in particular to extract valuable information about surface bonding and adsorption through calculating and analyzing the relative intensity of SERS spectra. Copyright (c) 2005 John Wiley & Sons, Ltd

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Section: Charge-transfer Enhancementmentioning

confidence: 99%

Density functional theory study of surface‐enhanced Raman scattering spectra of pyridine adsorbed on noble and transition metal surfaces

Duan

Ren

et al. 2005

J Raman Spectroscopy

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“…Broadly speaking, pyridine adsorbs on coinage metals either through the nonbonding pair of electrons on its ring nitrogen (vertical configuration) or through its π-electron system (horizontal adsorption). However, other adsorption configurations have been reported including tilted vertical phases ,, and the so-called α-pyridyl phase where coordination to the metal surface occurs via the ring nitrogen and an adjacent carbon atom after C–H bond cleavage. , The orientation adopted by pyridine on metal surfaces depends on the identity of the metal, − the packing density of its surface atoms, the electronic state of the metal, the vacuum/solution concentration of the adsorbate, and in the case of adsorption from solution, the pH of the electrolyte. Substitution effects also play a key role with reports of coordination through the substituent in both 4-cyanopyridine and pyridinecarboxlyates as well as other studies that indicate that the electron-donating ability of para-derivatized pyridines perturb the relative energetics associated with horizontal and vertical adsorption motifs. , The strong affinity of pyridine and its derivatives for metal surfaces coupled with its rich, yet seemingly well understood surface behavior, has made it popular in reports of nascent and developing surface characterization techniques based on vibrational spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Surface Enhanced Infrared Studies of 4-Methoxypyridine Adsorption on Gold Film Electrodes

2016

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This work uses electrochemical surface sensitive vibrational spectroscopy to characterize the adsorption of a known metal nanoparticle stabilizer and growth director, 4-methoxypyridine (MOP). Surface enhanced infrared absorption spectroscopy (SEIRAS) is employed to study the adsorption of 4-methoxypyridine on gold films. Experiments are performed under electrochemical control and in different electrolyte acidities to identify both the extent of protonation of the adsorbed species as well as its orientation with respect to the electrode surface. No evidence of adsorbed conjugated acid is found even when the electrolyte pH is considerably lower than the pKa. Through an analysis of the transition dipole moments, determined from DFT calculations, the SEIRA spectra support an adsorption configuration through the ring nitrogen which is particularly dominant in neutral pH conditions. Adsorption is dependent on both the electrical state of the Au film electrode as well as the presence of ions in the electrolyte that compete for adsorption sites at positive potentials. Combined differential capacitance measurements and spectroscopic data demonstrate that both a horizontal adsorption geometry and a vertical adsorption phase can be induced, with the former being found on negatively charged surfaces in acidic media and the latter over a wide range of polarizations in neutral solutions.

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“…This is of particular importance when studying centrosymmetric molecules because if the center of inversion is lost upon adsorption then both IR- and hyper-Raman-active modes may be observed in the Raman spectrum. There have been a series of surface-enhanced Raman scattering (SERS) studies on centrosymmetric adsorbates including benzene ( D 6 h ), − pyrazine ( D 2 h ), ,− and C 60 ( I h ). ,− In most of these reports, symmetry-forbidden modes were observed. For example, the SER spectra of benzene on cold-evaporated films contained the a 2u and e 2u vibrational modes, which are not Raman active for the free molecule ( D 6 h ).…”

Section: Introductionmentioning

confidence: 99%

Surface-Enhanced Hyper-Raman Scattering (SEHRS) on Ag Film over Nanosphere (FON) Electrodes: Surface Symmetry of Centrosymmetric Adsorbates

2006

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Electrochemical surface-enhanced hyper-Raman scattering (SEHRS) and surface-enhanced Raman scattering (SERS) of centrosymmetric molecules on Ag film over nanosphere (AgFON) electrodes are presented. The SEHR spectra of trans-1,2-bis(4-pyridyl)ethylene (BPE) at different potentials (vs Ag/AgCl) are presented for the first time, and a reversible potential tuning of the SEHR spectra of BPE is demonstrated. The SEHRS and SERS techniques were used to determine to what extent either site symmetry reduction or field gradient effects dictate the origin of the observed vibrational spectra. It is found that the SEHR and SER spectra for the molecules studied were distinctly different at all frequency regions at a fixed voltage, suggesting that centrosymmetry is largely retained upon adsorption to the AgFON surface and that field gradient effects are negligible. This work also shows that the SEHR spectra clearly depend on potential, whereas the SER spectra are essentially independent of potenial. It is determined that the combination of changes in deltaGads and the presence of coadsorbed counterions are responsible for altering the local symmetry of the adsorbate and only SEHRS has the sensitivity to detect these changes in the surface environment. Thus, SEHRS is a uniquely useful spectroscopic tool that is much more sensitive to the local adsorption environment than is SERS.

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An investigation of the adsorption of pyrazine and pyridine on nickel electrodes by in situ surface-enhanced Raman spectroscopy

Cited by 41 publications

References 81 publications

Density functional theory study of surface‐enhanced Raman scattering spectra of pyridine adsorbed on noble and transition metal surfaces

Density functional theory study of surface‐enhanced Raman scattering spectra of pyridine adsorbed on noble and transition metal surfaces

Surface Enhanced Infrared Studies of 4-Methoxypyridine Adsorption on Gold Film Electrodes

Surface-Enhanced Hyper-Raman Scattering (SEHRS) on Ag Film over Nanosphere (FON) Electrodes: Surface Symmetry of Centrosymmetric Adsorbates

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