Synthesis of nano-Ce 0.5 Zr 0.5 O 2 by absorption of ammonia into water-in-oil microemulsion in a rotor–stator reactor

Abstract

A gas-microemulsion reaction precipita- tion method was employed to prepare nano-Ce0.5- Zr0.5O2 by absorption of NH3 into water-in-oil (W/O) microemulsion in a rotor–stator reactor . The effects of different operating conditions including final pH of the microemulsion, reaction temperature, initial Ce3? and Zr4? concentration, rotation speed, and gas–liquid volumetric ratio were investigated. Nano-Ce0.5Zr0.5O2 with an average diameter of about 5.5 nm, a specific surface area of 215.6 m2/g and a size distribution of 4–8 nm was obtained under the optimum operating conditions. The as-prepared nano-Ce0.5Zr0.5O2 was loaded with Au to prepare nano-Au/Ce0.5Zr0.5O2 catalyst which was subsequently used for CO oxida- tion test. CO conversion rate reached 100 % at room temperature, indicating high catalytic activity of the nano-Au/Ce0.5Zr0.5O2 catalyst