Choi Mingi, Yong Kijung
Surface Chemistry Laboratory of Electronic Materials (SCHEMA) and Department of Chemical Engineering and Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Korea.
Nanoscale. 2014 Nov 21;6(22):13900-9. doi: 10.1039/c4nr04735d.
Vertically aligned high-quality single crystalline brookite TiO2 nanoarrays were synthesized for the first time using an environmentally benign one-step hydrothermal reaction. They have a unique bullet-shaped structure which has a length of 700-1000 nm and a width of 150-250 nm with a sharpened tip structure. By adjusting the concentration of NaOH in hydrothermal reaction, we could also synthesize other types of TiO2 nanostructures including anatase TiO2 nanotubes/nanowires. The morphologies and crystal structures of the products were confirmed by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. Their vertically aligned structures facilitate their application as photoanodes in photoelectrochemical cells, and the photoelectrochemical properties such as photocurrent density and open circuit voltage were measured in a three-electrode electrochemical cell with TiO2 nanoarrays, Ag/AgCl and a Pt flag as the working, reference and counter electrodes, respectively, incorporating a 0.1 M NaOH electrolyte solution. The fabricated brookite TiO2 nanoarrays exhibited a highly enhanced photocurrent density and a longer electron lifetime compared with anatase TiO2 nanoarrays with similar lengths.
首次采用环境友好的一步水热反应合成了垂直排列的高质量单晶板钛矿TiO₂纳米阵列。它们具有独特的子弹形结构，长度为700 - 1000 nm，宽度为150 - 250 nm，尖端结构尖锐。通过调节水热反应中NaOH的浓度，我们还可以合成其他类型的TiO₂纳米结构，包括锐钛矿TiO₂纳米管/纳米线。通过扫描电子显微镜、透射电子显微镜和X射线衍射分析对产物的形貌和晶体结构进行了确认。它们的垂直排列结构有利于其作为光阳极应用于光电化学电池中，并且在以TiO₂纳米阵列、Ag/AgCl和Pt片分别作为工作电极、参比电极和对电极的三电极电化学池中，加入0.1 M NaOH电解液，测量了光电流密度和开路电压等光电化学性质。与具有相似长度的锐钛矿TiO₂纳米阵列相比，所制备的板钛矿TiO₂纳米阵列表现出高度增强的光电流密度和更长的电子寿命。
