title: Preparation of γ-Fe2O3@C@MoO3 core/shell nanocomposites as magnetically recyclable catalysts for efficient and selective epoxidation of olefins.
abstract: Magnetic γ-Fe2O3@C@MoO3 core-shell structures were fabricated via a general approach and characterized by several techniques such as XRD, XPS, ICP-AES, Raman etc. The catalytic performance of them has been demonstrated in heterogeneously catalyzed oxidation of cyclooctene with tert-butyl hydroperoxide (tBuOOH) as an oxidant, and high conversion (100%) and selectivity (over 99%) were achieved with relatively low catalyst dosage under mild conditions. It should be emphasized that the hybrid catalyst could be easily separated by an external magnet and reused up to 9 times with no significant loss of activity and selectivity. The reaction mechanism over MoO3 is also discussed on the basis of the FTIR and XPS measurements. It is suggested that the high catalytic activity is related to the formation of the transition state, a Mo-alkyl peroxide and olefin complex, which is beneficial for an efficient oxygen atom transfer by converting the intermolecular process directly into an intramolecular process.
authors.affiliation: Hefei National Laboratory for Physical Science at Microscale, Department of Materials Science & Engineering & Collaborative Innovation Center of Suzhou Nono Science and Technology, University of Science & Technology of China, Hefei 230026, P. R. China. cqw@ustc.edu.cn.
authors.forename: Fushan
authors.initials: F
authors.lastname: Zhang
authors.forename: Haibo
authors.initials: H
authors.lastname: Hu
authors.forename: Hao
authors.initials: H
authors.lastname: Zhong
authors.forename: Nan
authors.initials: N
authors.lastname: Yan
authors.forename: Qianwang
authors.initials: Q
authors.lastname: Chen