Thermodynamically Driven One-Dimensional Evolution of Anatase TiO2 Nanorods: One-Step Hydrothermal Synthesis for Emerging Intrinsic Superiority of Dimensionality

详细信息    查看全文

• 作者：Jiazang Chen ; Hong Bin Yang ; Jianwei Miao ; Hsin-Yi Wang ; Bin Liu
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：October 29, 2014
• 年：2014
• 卷：136
• 期：43
• 页码：15310-15318
• 全文大小：546K
• ISSN：1520-5126

文摘

In photoelectrochemical cells, there exists a competition between transport of electrons through the porous semiconductor electrode toward the conducting substrate and back-reaction of electrons to recombine with oxidized species on the semiconductor鈥揺lectrolyte interface, which determines the charge collection efficiency and is strongly influenced by the density and distribution of electronic states in band gap and architectures of the semiconductor electrodes. One-dimensional (1D) anatase TiO₂ nanostructures are promising to improve charge transport in photoelectrochemical devices. However, the conventional preparation of 1D anatase nanostructures usually steps via a titanic acid intermediate (e.g., H₂Ti₃O₇), which unavoidably introduces electronic defects into the host lattice, resulting in undesired shielding of the intrinsic role of dimensionality. Here, we manage to promote the 1D growth of anatase TiO₂ nanostructures by adjusting the growth kinetics, which allows us to grow single-crystalline anatase TiO₂ nanorods through a one-step hydrothermal reaction. The synthesized anatase nanorods possess a lower density of trap states and thus can simultaneously facilitate the diffusion-driven charge transport and suppress the electron recombination. Moreover, the electronically boundary free nanostructures significantly enhance the trap-free charge diffusion coefficient of the anatase nanorods, which enables the emergence of the intrinsic superiority of dimensionality. By virtue of these merits, the anatase nanorods synthesized in this work take obvious advantages over the conventional anatase counterparts in photoelectrochemical systems (e.g., dye-sensitized solar cells) by showing more efficient charge transport and collection and higher energy conversion efficiency.