Laser-engineered metastable α-Fe2O3 nanodots with remarkable peroxidase-like catalytic activity for glucose sensing

Iron-based oxides have been a focus point in the study of nanozymes since the discovery of the intrinsic enzyme-like catalytic activity of Fe₃O₄. However, α-Fe₂O₃ has received limited attention due to its relatively low enzyme-like catalytic efficiency, despite its considerable industrial potential and wide-ranging applications. In this work, we present the synthesis of metastable α-Fe₂O₃ nanodots (M-Fe₂O₃ NDs) using an innovative laser processing technique. The formation of the metastable structure is primarily attributed to laser-induced high temperature fragmentation and rapid quenching. M-Fe₂O₃ NDs exhibit remarkable peroxidase-like activity, attributed to their high specific surface area, the rapid regeneration of surface Fe²⁺ facilitated by the elevated Fe²⁺/Fe³⁺ ratio, and the strong affinity for H₂O₂ resulting from their weak-crystalline structure. The catalytic efficiency of M-Fe₂O₃ NDs was found to be 17,438 times higher than that of α-Fe₂O₃ nanoparticles before laser treatment and 87 times higher than that of Fe₃O₄ NDs of comparable size. Additionally, we have developed a highly sensitive glucose sensor by integrating M-Fe₂O₃ NDs with glucose oxidase. This development paves the way for the design of more efficient Fe-based oxidase nanozymes and the enhancement of glucose sensors.