IN-SITU EC-AFM OBSERVATION ON Au(100) ELECTRODE IN ROOM TEMPERATURE IONIC LIQUID (EMImBF_4)

摘要

Surface structure of Au(100) with atomic resolution, as well as decay of mnultilayered islands located on Au(100), in a room temperature ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF_4)) under potential control have been investigated using electrochemical atomic force microscopy (EC-AFM). High resolution images in the potential range from -0.6 to 0.2 V (vs. Ag/Ag~+ in EMImBF_4), shows a fourfold symmetry with interatomic distance of 0.30 ±0.02 nm. This structure is consistent well with a bare and unreconstructed Au(100)-(1×1) structure. It is found that a nano-island located on Au(100) electrode collapses in the potential range between -1.05 V and 0.2 V (vs. Ag/Ag~+ in EMImBF_4). It is also found that the nano-island decays faster when Au(100) electrode potential is more positive. These EC-AFM observations reveal that Au(100) electrode in EMImBF_4 is quite similar to that observed in a sulfuric acid aqueous solution.