In situ generated Fe3C embedded Fe–N-doped carbon nanozymes with enhanced oxidase mimic activity for total antioxidant capacity assessment

In this work, we reported new Fe3C embedded Fe–N-doped carbon nanomaterials (Fe3C@Fe–N-CMs) generated in situ by the facile pyrolysis of Fe–Zn ZIF precursors. The resulting Fe3C@Fe–N-CMs were equipped with several desirable nanozyme features, including multiple efficient intrinsic active sites (i.e. Fe–Nx, Fe3C@C, and C–N moieties), large specific surface area and abundant mesoporous structures. As a result, these Fe3C@Fe–N-CMs displayed exceptional ability to mimic three enzymes: peroxidase, catalase and oxidase, while the Fe3C@Fe–N-CMs pyrolyzed at 800 °C, named CMs-800, showed the best enzyme-like properties. After systematically investigating the catalytic mechanism, we further explored the application of the oxidase-like properties of CMs-800 in the detection of the total antioxidant capacity (TAC) in beverages and tablets. This study not only provided a new approach to construct multifunctional carbon-based nanozymes, but also expanded the application of carbon nanozymes in the field of food quality and safety.