Study on the Oxidation of Chemical Compound at an Activated Polycrystalline Silver Surface Probed by SHG Technique

The oxidation of ethanol is an important process in chemical industry where fine particles of pure silver activated by adsorbed oxygen are used as the catalyst. However two different kinds of mechanism were proposed to explain this oxidation reaction but under controversies. One is the Langmuir-Hinshewood mechanism which claimed that the ethanol molecules were firstly adsorbed on the silver surface and then reacted with the adsorbed oxygen, the other, Eley-Rideal mechanism, claimed an one-step process is active that is the ethanol molecules in gaseous state reacted directly with the adsorbed oxygen when they collided on the silver surface. Hence it is suggested to have a new technique which might be able to discriminate these two mechanisms and here, we will report our recent study on this oxidation reaction by probing with the optical technique of second harmonic generation (SHG).