期刊
ELECTROCHEMISTRY COMMUNICATIONS
卷 132, 期 -, 页码 -出版社
ELSEVIER SCIENCE INC
DOI: 10.1016/j.elecom.2021.107146
关键词
Anodization; Atmospheric pressure; Growth rate; Growth kinetics
资金
- National Natural Science Foundation of China [51777097, 21401062]
The study demonstrates that reducing the atmospheric pressure during anodizing can enhance the growth rate of TiO2 nanotubes under the same conditions of NH4F electrolyte, current density, and temperature. Moreover, increasing the NH4F concentration results in higher porosity but lower growth rate of the nanotubes under the same temperature and current density conditions. These findings contradict the FAD theory and support the oxygen bubble model.
The growth mechanism of anodic TiO2 nanotubes has been a hot topic in recent years. The classical field-assisted dissolution (FAD) theory holds that the atmospheric pressure does not affect the growth of nanotubes, while the oxygen bubble model holds that the decrease of pressure is beneficial to the nanotube growth. In order to verify the oxygen bubble model, anodizing processes at three different pressures (0.1 MPa, 0.05 MPa and 0.005 MPa), three different currents and three different NH4F concentrations were studied. To the best our knowledge, some interesting results are obtained which cannot be obtained at standard atmospheric pressure (1 atm = 0.1 MPa). (1) In the same NH4F electrolyte, the same current density and the same temperature, the reduction of anodizing atmospheric pressure can improve the growth rate of TiO2 nanotubes. (2) Under the condition of the same temperature and current density, with the increase of NH4F concentration (0.3 wt%, 0.4 wt% and 0.5 wt%), the porosity of the nanotubes increases, and the growth rate of the nanotubes decreases obviously. These findings can serve as counterevidence to the FAD theory.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据