The adsorption and orientation of benzene and benzenesulfonic acid on platinum electrode surface were studied using cyclic voltammetry and in-situ reflection-absorption spectroscopy. For benzene/Pt system, benzene rings were adsorbed perpendicularly to the electrode surface in the potential range -0.6-0.0 V (vs. SCE), while in the range 0.0-0.8 V, flat orientation was found to be predominant. For benzenesulfonic acid/Pt system, the benzene rings were adsorbed perpendicularly to the electrode surface with SO3H group pointed away from the electrode in potential range -0.4-0.0 V, while in the range 0.0-0.1 V the predominant orientation of benzene rings was probably tilted flat, and at same time the SO3H group was adsorbed to the surface through two oxygen atoms.

Key words: ELECTRODE, PLATINUM, BENZENE, ADSORPTION, CYCLOVOLTAMGRAPH, ELECTROCHEMICAL METHOD, INFRARED REFLECTION SPECTROMETRY