title: Gold nanoparticles on mesoporous SiO(2)-coated magnetic Fe(3)O(4)spheres: a magnetically separatable catalyst with good thermal stability.
abstract: Fe3O4 spheres with an average size of 273 nm were prepared in the presence of CTAB by a solvothermal method. The spheres were modified by a thin layer of SiO2, and then coated by mesoporous SiO2 (m-SiO2) films, by using TEOS as a precursor and CTAB as a soft template. The resulting m-SiO2/Fe3O4 spheres, with an average particle size of 320 nm, a high surface area (656 m2/g), and ordered nanopores (average pore size 2.5 nm), were loaded with gold nanoparticles (average size 3.3 nm). The presence of m-SiO2 coating could stabilize gold nanoparticles against sintering at 500 °C. The material showed better performance than a conventional Au/SiO2 catalyst in catalytic reduction of p-nitrophenol with NaBH4. It can be separated from the reaction mixture by a magnet and be recycled without obvious loss of catalytic activity. Relevant characterization by XRD, TEM, N2 adsorption-desorption, and magnetic measurements were conducted.
authors.affiliation: Research Institute of Applied Catalysis, Shanghai Institute of Technology, Shanghai 201418, China. zhenma@fudan.edu.cn.
authors.forename: Huan
authors.initials: H
authors.lastname: Liu
authors.forename: Chao
authors.initials: C
authors.lastname: Lin
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ma
authors.forename: Hongbo
authors.initials: H
authors.lastname: Yu
authors.forename: Shenghu
authors.initials: S
authors.lastname: Zhou
mesh_terms: D005290:Ferric Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009596:Nitrophenols / Q000737:chemistry*; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D005290:Ferric Compounds; D009596:Nitrophenols; C000499:ferric oxide; D006046:Gold; D012822:Silicon Dioxide