Construct of Carbon Nanotube-Supported Fe2O3 Hybrid Nanozyme by Atomic Layer Deposition for Highly Efficient Dopamine Sensing

Abstract

The Fe₂O₃ nanozyme has been identified as the most promising alternative for the Fe₃O₄ nanozyme due to its relatively low toxic risk and good chemical stability. However, its enzyme-like activity is relatively low enough to meet specific application requirements. Furthermore, previous synthesis approaches have difficulties in fabricating ultra-small Fe₂O₃ nanoparticles with tunable size and suffer from agglomeration problems. In this study, atomic layer deposition (ALD) was used to deposit Fe₂O₃ on surfaces of carbon nanotubes to form hybrid nanozymes (Fe₂O₃/CNTs). ALD enables the preparation of ultrafine Fe₂O₃ nanoparticles with precise size control <1 nm, while CNTs could be served as promising support for good dispersibility and as an effective activity activator. Hence, the formed Fe₂O₃/CNTs exhibit excellent peroxidase-like activity with a specific peroxidase activity of 24.5 U mg^-1. A colorimetric method for sensing dopamine (DA) was established and presented good sensitivity with a limit of detection (LOD) as low as 0.11 μM. These results demonstrated that, in virtue of meticulous engineering methods like ALD, carbon nanomaterial-based hybrids can be developed as talented enzyme mimetic, thus paving a way for nanozyme design with desired activity and broadening their applications in biosensing and other fields.