کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5426747 | 1395900 | 2006 | 10 صفحه PDF | دانلود رایگان |
We describe the electrochemical preparation of an ultrathin copper sulfide film on Au(1 1 1) and its structural characterization by in situ STM. The first step, underpotential deposition of a Cu submonolayer from CuSO4/H2SO4 solution, is followed by two electrolyte exchanges for (i) Cu-free (blank) H2SO4 solution and (ii) NaOH/Na2S solution. The well-known (â3 Ã â3)R30° structure of the upd Cu layer is stable in the blank electrolyte for at least 2 h. After exposure to bisulfide, the Cu layer contracts and forms two-dimensional islands of two distinct ordered surface phases, i.e. a rectangular and, at higher potentials, a hexagonal phase, with Cu-free Au(1 1 1) regions between them, the latter exhibiting the characteristic (â3 Ã â3)R30°-S adlayer structure. Potential changes lead to a complex phase behaviour including HSâ â Sx oxidation/reduction and, at strongly anodic potentials, dissolution of the Cu adlayer.
Journal: Surface Science - Volume 600, Issue 13, 1 July 2006, Pages 2800-2809