苯胺在银和金电极上的表面增强拉曼光谱

聚苯胺作为性能较好的导电高聚物有很大的应用潜力,有关其聚合和导电机理的研究受到广泛重视。表面增强拉曼光谱(SERS)能现场(in situ)检测表面吸附分子、提

SURFACE ENHANCED RAMAN SPECTROSCOPIC STUDIES OF ANILINE ON Ag AND Au ELECTRODES

Surface enhanced Raman spectroscopy (SERS) provides a powerful means of obtaining information on adsorbate/surface interactions in view of its unique sensitivity~4]. With SERS, we started a preliminary study of the adsorption and subsequent electropolymerization of aniline on Ag and Au electrodes respectively. A set of potential-dependent SER spectra of aniline adsorbed at Ag electrodes are shown in figure 1. The charateristic adsorbate-surface vibrations around 306 and 226 cm~(-1) indicate that aniline is adsorbed via its N atom and at more positive potentials Cl~- is coadsorbed with aniline on the surface. With increasingly negative potentials, the considerable changes of the SER spectra are mainly due to that adsorbed aniline changes its orientation from perpendicular to parallel to the surface, which is in contrast to the case of Ag/pyridine system~7]. In another series of SERS experiments aniline was oxidized at Au electrodes as the potential was moved in positive direction (fig.2). The SER spectrum at +0.8 V is very similar to that of polyaniline at the same potential. It follows that the ppolymerization of aniline has taken place on the Au electrode. At less positive potentials (around +0.3 V) the distinct differences of the SER spectra with a high luminesence background are presumably due to the formation of oligomers of aniline at the surface.