2D phase transition of PF6 adlayers at the electrified ionic liquid/Au(111) interface

Abstract 2D phase transition of PF 6 adlayers at the electrified ionic liquid/Au(1 1 1) interface has been investigated by in situ STM. At the potential above −0.2 V vs Pt reference, PF 6 anions form Moire-like patterns on Au(1 1 1). When the potential is changed towards more negative values, the structural changes occur gradually, and a (√3 × √3) phase forms at approximate −0.45 V. More interestingly, the Moire-like patterns are found to coexist with the uncompressed structures in most cases. The formation of the ordered adlayers can be attributed to the different solvation of PF 6 in ionic liquid in comparison with aqueous solution.

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