Facile synthesis of Fe_3O_4/MWCNTs by spontaneous redox and their catalytic performance

摘要

Fe_3O_4 nanoparticles with a size range of 4-8 nm were formed by the spontaneous redox reaction between Fe~(3+) and multi-walled carbon nanotubes (MWCNTs). Cyclic voltammetry, Raman spectroscopy and x-ray photoelectron spectroscopy were employed to study the thermodynamic and dynamic conditions for the Fe_3O_4/MWCNTs formation. It is found that the high defect density of MWCNTs was thermodynamically favorable for the spontaneous reduction of Fe~(3+) ions and a reaction time of above 2.5h should be guaranteed. As the catalysts for benzene hydroxylation to phenol, the as-obtained Fe_3O_4/MWCNTs exhibit superior catalytic performance to those prepared by the hydrothermal method. Therefore, the spontaneous redox between the Fe~(3+) and MWCNTs supplies an attractive facile route for the preparation of Fe_3O+4 nanoscale catalysts.