Bandgap control of α-Fe₂O₃ nanozymes and their superior visible light promoted peroxidase-like catalytic activity

Abstract

Iron oxide nanoparticles (NPs) possessing peroxidase-like catalytic activity have been widely explored in recent decades, owing to their high stability against harsh conditions, low cost, flexibility in structure design and composition, adjustable activities and excellent biocompatibility in comparison with natural enzymes. Recently, a lot of great achievements have been made in this field of iron oxide nanozymes, however, this research has now reached a bottleneck in that the maximum activity enhancement is difficult to achieve via a material design. Hence, in this work, visible light was introduced to improve the peroxidase-like activity of FeO NPs synthesized via a combination of electrospinning technology and hydrothermal reaction. Our results showed that with the assistance of visible light, FeO NPs exhibited at least 2.2-fold higher peroxidase activity than those tested under darkness, confirming the superiorly visible light promoted peroxidase-like catalytic activity of FeO NPs. Furthermore, the affinity and maximum reaction velocity of FeO nanoflowers (bandgap = 1.78 eV) towards 3,3',5,5'-tetramethylbenanozymeidine (TMB) were at least over 3.7 and 4.3 times greater than in FeO nanocubes (bandgap = 2.08 eV), suggesting that the reaction performance of semiconductors could be controlled by proper adjustment of the bandgap. Moreover, the FeO NPs were also successfully utilized to detect glucose. Herein, we believe that the present work exhibits a fascinating perspective for peroxidase-like catalytic fields.

A Review on Metal- and Metal Oxide-Based Nanozymes: Properties, Mechanisms, and Applications

“…Furthermore, hot electrons from plasmon-excited AuNPs promoted charge separation at the interface of Au/α-FeOOH, resulting in efficient cycling of Fe 3+ /Fe 2+ to produce Fenton reaction. The introduction of visible light has increased the POD-type activity of Fe 2 O 3 NPs by at least 1.2 times in the research of Zhu et al [ 275 ]. They found that the light-related catalytic property of Fe 2 O 3 nanozymes was concerned with the bandgap and light absorption range, which were responsible for the barrier density generation and the light energy absorption.…”

Photo‐responsive nanozymes: Mechanism, activity regulation, and biomedical applications

“…Zhu et al regulated the pH value of the hydrothermal reaction system to change the morphology of Fe 2 O 3 NPs, which exhibited different bandgaps (1.78‐2.11 eV). Additionally, in comparison, the binding affinity and maximum reaction velocity of Fe 2 O 3 nanoflowers (1.78 eV) with TMB are at least 3.7 and 4.3 times higher than those of Fe 2 O 3 nanocubes (2.06 eV), respectively, which shows the catalytic performance can be specifically regulated by the crystal morphology with distinct crystallographic planes 61 . As shown in Figure 1A, Liu et al prepared Fe 3 O 4 nanocrystals with three diverse structures through similar hydrothermal reactions and further studied their POD‐like activities, which were structure‐dependent (in the order octahedra < triangular plates < cluster spheres) 77 .…”

Surface Engineering of Defective Hematite Nanostructures Coupled by Graphene Sheets with Enhanced Photoelectrochemical Performance

“…The Fe 2 O 3 nanocrystals were obtained as previously reported . Typically, the Fe­(acac) 3 /PVP composite nanofibers were used as Fe 2 O 3 precursor and were prepared by electrospinning a homogeneous solution containing 0.4 g of PVP (Mw ≈ 1.3 × 10 6 ), 3.5 mL of acetic acid, 3 mL of ethanol, and 0.8 g Fe­(acac) 3 with a flow rate of 0.3 mL/h at 17.5 kV.…”