Au Catalyst Decorated Silica Spheres: Synthesis and High-Performance in 4-Nitrophenol Reduction

A three-step synthesis has been developed to fabricate Au nanoparticle-decorated silica spheres as a catalyst (Au/SiO2). The Au/SiO2 catalyst was created by depositing uniformly Au nanoparticles with an average diameter of 5 nm on the SiO2 spheres by using optimal preparation conditions. Furthermore, the ratio of SiO2 and gold plays an important role for creating highly monodispersed Au nanoparticles. Compared with pure gold nanoparticles, the catalyst revealed admirable catalytic performance for the reduction reaction of 4-nitrophenol. The catalytic activities of Au/SiO2 samples were evaluated by the catalytic reduction of 4-nitrophenol under the liquid phase hydrogenation. Au/SiO2 catalysts with enough stability and activity can be recycled five times continuously for the reduction of 4-nitrophenol. The reduction mechanism of 4-nitrophenol and the catalytic action of the Au/SiO2 catalyst which has high reaction race constant k were discussed.