Gamma-radiation assisted preparation of Au/Fe3O4/poly(styrene-sodium styrene sulphonate) magnetic composite microspheres for catalysis

Magnetic Au/Fe 3 O 4 /poly(styrene-sodium styrene sulphonate) composite microspheres (Au/Fe 3 O 4 /P(St-NaSS) CMs) were successfully prepared via a gamma-radiation method. Au and Fe 3 O 4 were formed at the same time under irradiation and well dispersed on uniform P(St-NaSS) microspheres. The as-prepared CMs exhibit good catalytic properties and recyclable performances for the catalytic reduction of 4-nitrophenol (4-NP). The kinetic rate constants are 8.75 × 10 −3 s −1 and 7.71 × 10 −3 s −1 for two samples, respectively. The conversion rate of 4-NP can keep about 95% with catalysts after five cycles. They exhibit good magnetic behavior and have saturation magnetization value of about 9 emu g −1 , which can be easily separated from the solution under external magnetic field. This strategy is efficient and facile, which can be extended to fabricate other CMs.