title: Self-arrangement of nanoparticles toward crystalline metal oxides with high surface areas and tunable 3D mesopores.
abstract: We demonstrate a new design concept where the interaction between silica nanoparticles (about 1.5 nm in diameter) with titania nanoparticles (anatase, about 4 nm or 6 nm in diameter) guides a successful formation of mesoporous titania with crystalline walls and controllable porosity. At an appropriate solution pH (~1.5, depending on the deprotonation tendencies of two types of nanoparticles), the smaller silica nanoparticles, which attach to the surface of the larger titania nanoparticles and provide a portion of inactive surface and reactive surface of titania nanoparticles, dictate the direction and the degree of condensation of the titania nanoparticles, resulting in a porous 3D framework. Further crystallization by a hydrothermal treatment and subsequent removal of silica nanoparticles result in a mesoporous titania with highly crystalline walls and tunable mesopore sizes. A simple control of the Si/Ti ratio verified the versatility of the present method through the successful control of mean pore diameter in the range of 2-35 nm and specific surface area in the ranges of 180-250 m(2) g(-1). The present synthesis method is successfully extended to other metal oxides, their mixed oxides and analogues with different particle sizes, regarding as a general method for mesoporous metal (or mixed metal) oxides.
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.
authors.forename: Hyung Ik
authors.initials: HI
authors.lastname: Lee
authors.affiliation: SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 440-746 Korea.
authors.forename: Yoon Yun
authors.initials: YY
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.
authors.forename: Dong-Uk
authors.initials: DU
authors.lastname: Kang
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.
authors.forename: Kirim
authors.initials: K
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.|SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 440-746 Korea.
authors.forename: Young-Uk
authors.initials: YU
authors.lastname: Kwon
authors.affiliation: Department of Chemistry, Sungkyunkwan University, Suwon, 440-746, Republic of Korea.|SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon, 440-746 Korea.
authors.forename: Ji Man
authors.initials: JM
authors.lastname: Kim