Scanning tunneling microscopy observation of the origin of electrochemical promotion and metal-support interactions

摘要

Scanning tunneling microscopy (STM) was used to investigate the surface of Pt single crystal catalyst surfaces interfaced with O~2-conducting catalyst supports under conditions simulating electrochemical promotion and metal-support interactions. In both cases STM has clearly shown the reversible migration on the catalyst surface of promoting O~(2-) species which are entirely distinct from normally chemisorbed oxygen originating from the gas phase. These observations provide useful information for the mechanism of electrochemical promotion and metal-support interactions, reveal the existence and fast migration of O~(2-), a most effective anionic promoter, on metal surfaces and underline its role in inducing the phenomena of electrochemical promotion and of metal-support interactions.