Synthesis of CeO hollow microspheres with oxidase-like activity and their application in the catalytic degradation of p-nitrophenol.

CeO materials have received wide attention given their oxidase-like activity without the need for an unstable oxide substrate in the catalytic process. Nevertheless, their application and mechanism in the catalytic oxidation of refractory organic pollutants needs further study. Herein, CeO hollow microspheres (HMS) with an intrinsic oxidase-like activity were synthesised via a template-free hydrothermal method and their effectiveness in degrading p-nitrophenol(p-NP) was investigated. HMS showed a maximum p-NP degradation rate of 76.5% at a CeO dosage of 40 mg, 2 h reactive time, at 30°C and pH of 4.8 when the concentration of p-NP was 20 mg L. The catalytic activity of CeO HMS also exhibited good thermal stability and reusability. These results provide strong evidence that CeO HMS can be utilised as an oxidase mimetic for the efficient catalytic degradation of refractory organic pollutants. A possible mechanism for the degradation of p-NP is also discussed.