Cu在HOPG上电化学沉积的原子分辨ECSTM现场观测

Study of Copper Electrodeposition on HOPG by in Situ Electrochemical Scanning Tunneling Microscope with Atomic Resolution

电化学扫描隧道显微镜(ECSTM)因其能提供真实空间的原子分辨图象而成为现场研究电极表面结构的最强有力的手段之一。近来,欠电位沉积(UPD)得到日益广泛的研究,人们观察到了Cu在Au(111)和Pt(111)上的UPD层的原子结构。而在金属体相沉积的ECSTM研究中所得图象的分辨率较低。我们用ECSTM在控电位下对Cu在高序石墨(HOPG)

A home-built in situ electrochemical scanning tunneling microscope (ECSTM) was applied to investigation of the electrodeposition of Cu on HOPG in CuSO4 solution under potential control. During potential cycling, the deposition and dissolution processes of Cu were clearly observed. At about-250 mV(vs. Cu2+/Cu) it was found that the STM images changed with time. A regular hexagonal lattice was observed first, with a next-neighbour atomic distance of 0. 40±0. 02 nm, which is considered to be HOPG(0001)-(3^(1/2)×3^(1/2))R30° Cu adlattice. Following that, Cu(111) and Cu(110) faces appeared, both showing long range-corrugation patterns.