Showing papers by "Bin Ren published in 1999"
TL;DR: The surface enhanced Raman scattering (SERS) properties of rhodium films electrodeposited onto a SERS-active gold substrate are examined as a function of overlayer thickness, using carbon monoxide and thiocyanate as chemisorbate probes in aqueous solution as mentioned in this paper.
Abstract: The surface-enhanced Raman scattering (SERS) properties of rhodium films electrodeposited onto a SERS-active gold substrate are examined as a function of overlayer thickness, using carbon monoxide and thiocyanate as chemisorbate probes in aqueous solution. Although the adsorbate Raman signals obtained for ultrathin (≤10 monolayers, ML) Rh layers emanate from the gold template, a significant or even dominant SERS component for thicker films is identified as arising instead from the transition-metal overlayer itself. The latter contribution was diagnosed and characterized from similar experiments undertaken using SERS-inactive gold and carbon substrates, and from the observation of comparable Raman enhancements obtained with green (514.5 nm) as well as red (632.8 nm) excitation. While the surface enhancement factors for these layers, of the order of 103, are markedly less than those obtained for ultrathin films on SERS-active gold, the signals even for very weak Raman scatterers (such as adsorbed hydrogen) ...
71 citations
TL;DR: In this article, confocal microprobe Raman spectroscopy was used to investigate hydrogen adsorption at platinum electrodes in acidic solution and showed that the nature and the bonding configuration of the surface hydrogen are remarkably different in the UPD and OPD regions of hydrogen evolution.
47 citations
TL;DR: In this paper, a surface roughening procedure is used to obtain good-quality surface Raman signals from transition metals, with the surface enhancement factor ranging from one to three orders of amplification.
36 citations
TL;DR: In this paper, the authors investigated hydrogen adsorption at platinum electrodes by B3LYP quantum-chemical calculations and found that the large tuning rate of the Pt-H frequency should be attributed to the work function shift with the change of electrode potential.
33 citations
TL;DR: In this paper, confocal microprobe Raman spectroscopy and quantum chemistry calculation was used to investigate hydrogen adsorption at platinum electrodes in acidic solution. But no Pt-H band could be detected in the strongly bound hydrogen adaption region.
Abstract: Hydrogen adsorption at platinum electrodes in acidic solution is investigated by confocal microprobe Raman spectroscopy and quantum chemistry calculation. Vibration for on-top adsorbed hydrogen against a platinum surface is observed in the potential region of hydrogen evolution. With the negative moving of the potential, there is a red shift of Pt-H vibrational frequency. No Pt-H band could be detected in the strongly bound hydrogen adsorption region. A very weak and broad band for the terminal Pt-H vibration in the weakly bound hydrogen adsorption region is discernible when the underpotential deposition hydrogens are saturated. Ab initio cluster model calculations indicate that the large tuning rate of the Pt-H frequency should be attributed to the work function shift with the change of electrode potential. The calculation results show that the spectroscopic properties of the Pt-H bond are sensitive to the surface coverage. The experimentally observed red shift of Pt-H frequency with a decrease of electrode potential would originate from the lateral interaction of Pt-H bonds.
15 citations