Science. 1991 Jan 11;251(4990):183-6. doi: 10.1126/science.251.4990.183.
The atomic force microscope (AFM) was used to image an electrode surface at atomic resolution while the electrode was under potential control in a fluid electrolyte. A new level of subtlety was observed for each step of a complete electrochemical cycle that started with an Au(111) surface onto which bulk Cu was electrodeposited. The Cu was stripped down to an underpotential-deposited monolayer and finally returned to a bare Au(111) surface. The images revealed that the underpotential-deposited monolayer has different structures in different electrolytes. Specifically, for a perchloric acid electrolyte the Cu atoms are in a close-packed lattice with a spacing of 0.29 +/- 0.02 nanometer (nm). For a sulfate electrolyte they are in a more open lattice with a spacing of 0.49 +/- 0.02 nm. As the deposited Cu layer grew thicker, the Cu atoms converged to a (111)-oriented layer with a lattice spacing of 0.26 +/- 0.02 nm for both electrolytes. A terrace pattern was observed during dissolution of bulk Cu. Images were obtained of an atomically resolved Cu monolayer in one region and an atomically resolved Au substrate in another in which a 30 degrees rotation of the Cu monolayer lattice from the Au lattice is clearly visible.
原子力显微镜（AFM）被用于在电势控制下对处于流体电解质中的电极表面进行原子分辨率成像。在一个完整的电化学循环中，每个步骤都观察到了新的微妙之处，该循环从 Au(111)表面开始，在该表面上电沉积了大块的 Cu。Cu 被剥离到欠电势沉积的单层，最终返回到裸露的 Au(111)表面。图像显示，欠电势沉积的单层在不同的电解质中有不同的结构。具体而言，对于高氯酸电解质，Cu 原子处于具有 0.29 +/- 0.02 纳米（nm）间距的密排晶格中。对于硫酸盐电解质，它们处于更开放的晶格中，间距为 0.49 +/- 0.02 nm。随着沉积的 Cu 层变厚，Cu 原子收敛到具有 0.26 +/- 0.02 nm 间距的（111）取向层，对于两种电解质都是如此。在溶解大块 Cu 时观察到平台图案。在一个区域中获得了原子分辨的 Cu 单层的图像，在另一个区域中获得了原子分辨的 Au 衬底的图像，其中 Cu 单层晶格相对于 Au 晶格的 30 度旋转清晰可见。
