Zhang Lijuan, Zhang Yi, Zhang Xuehua, Li Zhaoxia, Shen Guangxia, Ye Ming, Fan Chunhai, Fang Haiping, Hu Jun
Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Langmuir. 2006 Sep 12;22(19):8109-13. doi: 10.1021/la060859f.
Electrogenerated microscale bubbles that are confined at the electrode surface have already been extensively studied because of their significant influence on electrochemistry. In contrast, as far as we know, whether nanoscale bubbles exist on the electrode surface has not been experimentally confirmed yet. Here, we report the observation of electrochemically controlled formation and growth of hydrogen nanobubbles on bare highly oriented pyrolytic graphite (HOPG) surface via in-situ tapping mode atomic force microscopy (TMAFM). By using TMAFM imaging, we observed that electrochemically generated hydrogen gas led to the formation of nanobubbles at the HOPG surface. We then employed a combination of techniques, including phase imaging, ex-situ degassing, and tip perturbation, to confirm the gas origin of such observed nanobubbles. We further demonstrated that the formation and growth of nanobubbles could be well controlled by tuning either the applied voltage or the reaction time. Remarkably, we could also monitor the evolution process of nanobubbles, that is, formation, growth, coalescence, as well as the eventual release of merged microbubbles from the HOPG surface.
由于其对电化学有重大影响，限制在电极表面的电生成微尺度气泡已得到广泛研究。相比之下，据我们所知，电极表面是否存在纳米尺度气泡尚未得到实验证实。在此，我们报告通过原位敲击模式原子力显微镜（TMAFM）观察到在裸露的高度取向热解石墨（HOPG）表面上氢纳米气泡的电化学控制形成和生长。通过使用TMAFM成像，我们观察到电化学产生的氢气导致在HOPG表面形成纳米气泡。然后我们采用了包括相成像、非原位脱气和针尖扰动在内的多种技术组合，以确认所观察到的此类纳米气泡的气体来源。我们进一步证明，通过调节施加电压或反应时间，可以很好地控制纳米气泡的形成和生长。值得注意的是，我们还可以监测纳米气泡的演变过程，即形成、生长、合并以及最终从HOPG表面释放合并的微气泡。
