A facile synthesis of FeO/nitrogen-doped carbon hybrid nanofibers as a robust peroxidase-like catalyst for the sensitive colorimetric detection of ascorbic acid.

In recent years, the fabrication of functional nanostructures with multicomponents for a variety of novel biosensors has received considerable attention due to their synergistic improved sensitivity. Herein, we report a facile approach for the preparation of FeO/nitrogen-doped carbon (FeO/N-C) hybrid nanofibers, and construct a sensing platform for the sensitive colorimetric detection of HO and ascorbic acid (AA). During the synthetic process, a discontinuous layer of polypyrrole (PPy) is first polymerized in situ on the surface of the α-FeO nanofibers under hydrothermal reaction using α-FeO nanofibers as both a template and an oxidant. Then the prepared α-FeO/PPy nanofibers are converted into FeO/N-C hybrid nanofibers through pyrolysis with a thermochemical reduction process. The resulting FeO/N-C hybrid nanofibers are used as a novel peroxidase mimic towards the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of HO, with a superior catalytic activity over individual α-FeO nanofibers, α-FeO/PPy nanofibers, FeO/C nanofibers, and commercial FeO nanoparticles. Based on the high peroxidase-like activity of FeO/N-C hybrid nanofibers, a sensing platform for the colorimetric detection of AA is developed. A good linear relationship from 0 to 50 μM and a detection limit of 0.04 μM are achieved. This work offers a new method for the preparation of FeO/N-C hybrid nanofibers and presents new potential applications in biosensing, medical diagnostics and environmental monitoring.