For the first time, we have obtained surface Raman spectra of dissociative adsorption of methanol at bare Pt electrodes of different surface roughness factors from 60 to 200 by using a confocal Raman microscope and a ...
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For the first time, we have obtained surface Raman spectra of dissociative adsorption of methanol at bare Pt electrodes of different surface roughness factors from 60 to 200 by using a confocal Raman microscope and a specific surface roughening procedure. Two bands at around 1 830 cm-1 and 2 040 cm-1 respectively have been assigned to the CO streching vibration of the dissociatively adsorbed CO as the poison Intermediate on the surface. In the low frequency region, the two correlated bands at ca 413 cm-1 and 494 cm-1 respectively provide a clear vibrational information that there exist the linear bonded Pt-CO and bridge bonded P’jO. On the Pt electrode with mild roughness, the Raman signal of CO peared at -0. 4 V, whereas it was still observable on the Pt electrode with high *** reveals that the CO-substrate interaction is stronger for the platinum with the higher surface roughness, at least partly due to the supercluster interaction of the roughened electrode. In addition, the highly rough surface may be favorable to the formation of island CO,thus enhance the interaction between molecules. It has been shown that surface Raman spectroscopy has two advantages: first, It provides a uniquely sensitive probe for obtaining surface-adsorbate vibration information in the low frequency region which is typically not accessible to IR spectroscopy. Second, it can be applied to the study of highly roughened electrodes that are common for practical use. With its notable improvements in detection sensitivity and functions, Raman spectroscopy will probably become a powerful tool to in-situ study electrocatalysis of practical importance.
Au/PATP/PANI (polyaniline) film electrode was prepared by voltamometry in 0.5 mol/L aniline/0.5 mol/L HClO 4 from -0.2—0.8 V at 100 mV/s after selfassembling PATP(4aminothiophenol) on bare Au. The potential dependenc...
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Au/PATP/PANI (polyaniline) film electrode was prepared by voltamometry in 0.5 mol/L aniline/0.5 mol/L HClO 4 from -0.2—0.8 V at 100 mV/s after selfassembling PATP(4aminothiophenol) on bare Au. The potential dependence of photocurrent and the photocurrent spectra of Au/PATP/PANI film electrode were obtained. The potential dependence of photocurrent showed that all of the three forms(oxidized/partiallyoxidized/reduced) of PANI film had both anodic photocurrent and cathodic photocurrent. The halfoxidized PANI film had a great photoelectrochemical response. The photocurrent spectra of Au/PATP/PANI film electrode showed both half oxidized and reduced PANI film had the characteristics of subbandgap photocurrent spectra and followed Fowler rule(IPCE 1/2 =E threshold + b hν ). A photoelectrochemical model on internal photoemission at insulator covered metal was presented to interpret it, which agreed with the model of granular metal island. The model assumed metallic polymer particles embedded in the nonmetallic matrix, while, Au/PATP/PANI/TiO 2 film electrode was prepared by electrodeposition in TiCl 3 solution (pH≈2.2). The photocurrent spectra of Au/PATP/PANI/TiO 2 film possessed the photoelectrochemical characteristics of both TiO 2 and PANI. The Au/PATP/PANI/TiO 2 film was expected to improve the efficient absorption of solar light.
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