Perylene diimide‐modified magnetic γ‐Fe2O3/CeO2 nanoparticles as peroxidase mimics for highly sensitive colorimetric detection of Vitamin C

Perylene diimide‐modified magnetic γ‐Fe 2 O 3 /CeO 2 nanoparticles (γ‐Fe 2 O 3 /CeO 2 ‐PDI) were prepared and exhibited excellent peroxidase‐like activity. The samples were characterized by HR‐TEM, XRD, Raman, N 2 adsorption, magnetic strength and XPS. The obtained γ‐Fe 2 O 3 /CeO 2 ‐PDI had size of 10~20 nm with high specific surface area of 77 m 2 /g, and could be easily separated from the aqueous solution by using a magnet, which are in favor of its practical application. Due to the decoration of PDI, the γ‐Fe 2 O 3 /CeO 2 ‐PDI possessed more surface defects (Ce 3+ ) and active oxygen species than that of γ‐Fe 2 O 3 /CeO 2 , resulting in the outstanding catalytic performance. And the composite catalyst also showed highly sensitive and selectivity toward VC with a limit of detection of 0.45 μM. Based on the fluorescent results, a possible hydroxyl radical (•OH) catalytic mechanism was proposed. It is believed that the as‐prepared γ‐Fe 2 O 3 /CeO 2 ‐PDI nanoparticles are promising biosensors applied for biomedical and food analysis.