Synthesis of CeO2 nanoparticles by sacrificial Mg powder with abundant oxygen vacancies and efficiently photocatalytic activity

•Single crystal CeO2 nanoparticles were synthesized by a novel sacrificial metal method.•The ultrasonic treatment is beneficial to generate oxygen vacancies and lower particle size.•The CeO2 nanoparticles exhibits superior photocatalytic degradation of tetracycline. A novel sacrificial metal method is adopted to synthesize CeO2 nanoparticles with abundant oxygen vacancies and efficient photocatalytic activity. The CeO2 nanoparticles (U-Mg-CeO2) are obtained just with sacrificial Mg powder in ceriumsaltsolutions under ultrasonic treatment. The U-Mg-CeO2 exhibits single crystal structure and the diameter is about 10 nm. The ESR and other characterization results show that U-Mg-CeO2 contains abundant oxygen vacancies on the surface. The U-Mg-CeO2 photodegrade tetracycline (TC) under sun-light reaching 75 % with the amount of catalyst 0.25 g/L. The novel synthesis method, higher surface area, oxygen vacancy defects are useful to improve the catalytic performance. This novel method may shed light on synthesis of other highly active catalysts.