Polar Zinc Oxide Surface in Electrolyte Solutions; An Atomic View of Reconstruction, Hydration and Surface states
Polar Zinc Oxide Surface in Electrolyte Solutions; An Atomic View of Reconstruction, Hydration and Surface states
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电解质溶液中的极性氧化锌表面；
DOI：
10.1039/d1cp02371c
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发表时间：
2021
影响因子：
3.3
通讯作者：
and Seiichiro Nakabayashi,
中科院分区：
文献类型：
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作者：
Yudai Samejima;Naritaka Kobayashi;and Seiichiro Nakabayashi,
采用原子分辨液-环境原子力显微镜（AFM）和电化学方法研究了锌端（Zn-） ZnO（0001）表面在电解质溶液中的稳定机理。电化学测量的Zn-ZnO（0001）表面平带电位的pH依赖性表明，OH基团在1-13的宽pH范围内吸附在（0001）表面。Zn-ZnO（0001）表面的原子尺度AFM图像在碱性溶液中显示出有序的氢氧化物上层结构，而在酸性溶液中显示出无序的结构，这可能是由于吸附的OH基团快速扩散所致。此外，在酸性溶液中，Zn-ZnO（0001）表面的o端阶边密度高于在碱性溶液中。根据这些发现，我们得出Zn-ZnO（0001）表面多余的正电荷被吸附的OH基团和o端台阶边补偿。在酸性溶液中，需要更高密度的o端阶跃边来进行电荷补偿。此外，电化学AFM还发现，在阶梯取向无序的局部过渡区发生了依赖电位的可逆表面重构。我们的结论是，重建补偿了局部过渡区多余的表面电荷，这些电荷是由电位依赖的局部表面状态引起的。
The stabilization mechanism of the Zn-terminated (Zn-) ZnO(0001) surface in electrolyte solutions has been investigated by using atomic-resolution liquid-environment atomic force microscopy (AFM) and an electrochemical method. The electrochemically measured pH dependence of the flat band potential of the Zn–ZnO(0001) surface indicated the adsorption of OH groups onto the (0001) surface in the wide pH range of 1–13. Atomic-scale AFM images of the Zn–ZnO(0001) surface showed a well-ordered hydroxide superstructure in an alkaline solution but a disordered structure in an acidic solution, which is probably attributed to the rapid diffusion of the adsorbed OH groups. Furthermore, the density of the O-terminated step edge on the Zn–ZnO(0001) surface in an acidic solution was higher than that in an alkaline solution. From these findings, we concluded that the excess positive charges of the Zn–ZnO(0001) surface are compensated by the adsorbed OH groups and the O-terminated step edges. In acidic solutions, a higher density of the O-terminated step edge is required for charge compensation. In addition, it was found that potential-dependent reversible surface reconstruction occurs in the local transition area with disordered step orientation by electrochemical AFM. We concluded that the reconstruction compensates the excess surface charges of the local transition area which are induced and varied by potential-dependent local surface states.