Copper-cobalt Bimetallic Oxides-doped Alumina Hollow Spheres: a Highly Efficient Catalyst for Epoxidation of Styrene

Copper-cobalt bimetallic oxides-doped alumina hollow spheres(CuCo/AHS)were labricatcd through the sacrificial carbonaceous template strategy.The dependence of the physicochemical properties and morphologies of CuCo/AHS on the composition of copper and cobalt in CuxCoy/AHS(x/y=9/1,7/3,5/5,and 3/7)was characterized bv means of X-ray powder diffraction,nitrogen physisorption,atomic adsorption spectroscopy,scanning electron microscopy,transmission electron microscopy and X-ray photoelectron spectroscopy.Among these catalysts, Cu7-Co3/AHS catalyst exhibited perfect hollow sphere structure,thin wall,and big pore size.The calcined catalysts were examined for the epoxidation of styrene with tert-butyl hydroperoxide as oxidant.Compared with the monometallic counterparts(Cu/AHS and Co/AHS)and other CuxCoy/AHS catalysts,Cu7Co3/AHS catalyst showed higher performance,yielding a styrene conversion of 64.6% with 93.0% selectivity toward styrene oxide.In addition,the strong interaction of Cu^2+or Co^2+ with AHS ensured good stability after four consecutive reactions.