Cerium oxide (CeO2) is a well-known antioxidant with the ability to scavenge reactive oxygen species due to its unique electronic structure and chemical properties. Although many methods to enhance the antioxidant activity of CeO2 have been reported, its antioxidant activity is still not high enough, and some enhancement effects are limited by the material concentration. There are also some CeO2 obtained with high antioxidant activity at high concentrations, which is not conducive to the application of biomedicine. Therefore, it is urgent to obtain CeO2 material with low cell cytotoxicity, high antioxidant activity and wide application range. In this work, rod-like metal organic framework derived CeO2 (CeO2-MOF) was prepared by a simple method. Compared with the CeO2 nanorods prepared by hydrothermal method, it shows better antioxidant activity compared with the CeO2 nanorods prepared by hydrothermal method. Moreover, the advantage of CeO2-MOF’s antioxidant activity is not affected by the hydroxyl radical and material concentrations The reason why CeO2-MOF has higher antioxidant activity should be attributed to its higher Ce3+ content and larger specific surface area. In addition, CeO2-MOF also exhibits low cytotoxicity to HeLa cells and PC 12 cells in vitro. The strategy of using MOF as a structural and compositional material to create CeO2 provides a new method to explore highly efficient and biocompatible CeO2 for practical applications.

The modification of Au nanoparticles can improve the antioxidant activity of CeO2, however, nano Au/CeO2 has also met some problems such as low atomic utilization, the limit of reaction conditions, and high cost. Au single atom catalysts can well solve the above-mentioned problems, but there are some contradictory results about the activity of single atom Au1/CeO2 and nano Au/CeO2. Here, we synthesized rod-like Au single atom Au/CeO2 (0.4% Au1/CeO2) and nano Au/CeO2 (1% Au/CeO2, 2% Au/CeO2 and 4% Au/CeO2), and their antioxidant activity from strong to weak is 0.4% Au1/CeO2, 1% Au/CeO2, 2% Au/CeO2 and 4% Au/CeO2, respectively. The higher antioxidant activity of 0.4% Au1/CeO2 is mainly due to the high Au atomic utilization ratio and the stronger charge transfer between Au single atoms and CeO2, resulting in the higher content of Ce3+. Due to the coexistence of Au single atoms and Au NPs in 2% Au/CeO2, the antioxidant activity 2% Au/CeO2 is higher than that of 4% Au/CeO2. And the enhancement effect of Au single atoms was not affected by the concentration of ·OH and material concentration. These results can promote the understanding of the antioxidant activity of 0.4% Au1/CeO2 and promote its application.