title: pH-induced simultaneous synthesis and self-assembly of 3D layered beta-FeOOH nanorods.
abstract: Higher-ordered architectures self-assembly of nanomaterials have recently attracted increasing attention. In this work, we report a spontaneous and efficient route to simultaneous synthesis and self-assembly of 3D layered beta-FeOOH nanorods depending on a pH-induced strategy, in which the continuous change of pH is achieved by hydrolysis of FeCl(3).6H(2)O in the presence of urea under hydrothermal conditions. The electron microscopy observations reveal that the square-prismic beta-FeOOH nanorods are self-assembled in a side-by-side fashion to form highly oriented 2D nanorod arrays, and the 2D nanorod arrays are further stacked in a face-to-face fashion to form the final 3D layered architectures. On the basis of time-dependent experiments, a multistage reaction mechanism for the formation of the 3D layered beta-FeOOH nanorods architecture is presented, involving the fast growth and synchronous self-assembly of the nanorods toward 1D, 2D, and 3D spontaneously. The experimental evidence further demonstrates that the urea-decomposition-dependent pH continuously changing in the solution, spontaneously altering the driving force competition between the electrostatic repulsive force and the attractive van der Waals force among the nanorods building blocks, is the essential factor to influence the self-assembly of the beta-FeOOH nanorods from 1D to 3D.
authors: State Key Laboratory for Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, PR China.
authors: Xiao-Liang
authors: XL
authors: Fang
authors: Yue
authors: Y
authors: Li
authors: Cheng
authors: C
authors: Chen
authors: Qin
authors: Q
authors: Kuang
authors: Xiang-Zhi
authors: XZ
authors: Gao
authors: Zhao-Xiong
authors: ZX
authors: Xie
authors: Su-Yuan
authors: SY
authors: Xie
authors: Rong-Bin
authors: RB
authors: Huang
authors: Lan-Sun
authors: LS
authors: Zheng