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One‐Step Synthesis of Highly Ordered Mesoporous Silica Monoliths with Metal Oxide Nanocrystals in their Channels
Author(s) -
Yang H.,
Lu Q.,
Gao F.,
Shi Q.,
Yan Y.,
Zhang F.,
Xie S.,
Tu B.,
Zhao D.
Publication year - 2005
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200500026
Subject(s) - materials science , nanocomposite , oxide , nanocrystal , nanorod , mesoporous material , chemical engineering , metal , nanotechnology , non blocking i/o , mesoporous silica , nanoparticle , nanowire , catalysis , organic chemistry , metallurgy , chemistry , engineering
A simple, one‐step synthetic route to prepare ordered mesoporous silica monoliths with controllable quantities of metal oxide nanocrystals in their channels is presented. The method is based on the assisted assembly effect for mesostructure‐directing of the metal complexes formed by the interaction of metal ions with the –O– groups of copolymers. Highly ordered hexagonal silica monoliths, loaded with various metal oxide nanocrystals, including those of Cr 2 O 3 , MnO, Fe 2 O 3 , Co 3 O 4 , NiO, CuO, ZnO, CdO, SnO 2 , and In 2 O 3 , can be obtained by this one‐step pathway. In the NiO/SiO 2 nanocomposite, nickel oxide nanorods with face‐centered cubic lattices are formed at low doping ratios, and they can be transformed into nanowires by increasing the quantities of the precursors. In the Fe 2 O 3 /SiO 2 nanocomposites, a one‐dimensional assembly of iron oxide nanoparticles is observed. In the In 2 O 3 /SiO 2 nanocomposites, single crystal nanowires with high aspect ratios are obtained. For the other metal oxide nanocomposites, including Cr 2 O 3 , MnO, Co 3 O 4 , CuO, ZnO, CdO, and SnO, only crystalline nanorods are obtained. N 2 sorption results of the metal oxide/SiO 2 mesostructured nanocomposites reveal that nanocrystals inside the pores do not severely decrease the pore volume or the Brunauer–Emmett–Teller (BET) surface area of the mesoporous silica host. The bandgaps of SnO 2 and In 2 O 3 nanocrystals, calculated from UV‐vis spectra, are much larger than the corresponding bulk materials, implying the quantum confinement effect in the small particles. Co 3 O 4 /SiO 2 mesostructured nanocomposites catalyze the complete combustion of CH 4 . These studies provide a new and simple method for templating synthesis of metal oxide nanostructures.