Synergistic effect of ternary electrospun TiO2/Fe2O3/PPy composite nanofibers on peroxidase-like mimics with enhanced catalytic performance

Abstract

In this work, we demonstrate the fabrication of polypyrrole (PPy) decorated TiO₂/Fe₂O₃ (TiO₂/Fe₂O₃/PPy) composite nanofibers with a core–shell structure as an artificial enzyme system with a high peroxidase-like activity. The TiO₂/Fe₂O₃ nanofibers with a diameter in the range of 40–150 nm and a relatively narrow distribution of diameter size are prepared via an electrospinning technique and followed by a calcination process. Then we are able to in situ polymerize a layer of PPy on the surface of the TiO₂/Fe₂O₃ nanofibers by using Fe₂O₃ on the surface of nanofibers as an oxidant. The resulting ternary TiO₂/Fe₂O₃/PPy composite nanofibers exhibit an enhanced peroxidase-like activity toward the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂ over independent TiO₂, Fe₂O₃ and TiO₂/Fe₂O₃ composite nanofibers due to the synergistic effect. On the basis of the high peroxidase-like activity, a simple approach for the colorimetric detection of H₂O₂ with a detection limit of 2.4 μM and a linear detection range from 2 to 50 μM has been proposed. This work offers a new way for manipulating the enzyme-like performance of electrospun nanofibers for a wide range of potential applications in biosensing and environmental monitoring.