通过电化学方法和紫外-可见光度法研究了Fe3O4纳米材料的类似过氧化物酶的催化性质。并对比不同尺寸（11nm、20nm、150nm）的Fe3O4性能，发现其催化活性随着颗粒尺寸的减小而增大。新开展了电化学分析方法是通过典型的酶反应底物和催化反应产物的电化学响应电流来体现Fe3O4的类似酶的活性。
In this study, we focus on peroxidase-like catalytic properties of Fe3O4 NPs. The Fe3O4 NPs with three different sizes (11, 20, and 150 nm), synthesized by chemical coprecipitation and sol-gel methods, can all catalyze the reaction of the typical peroxidase substrate 3, 3ˊ, 5ˊ, 5-tetramethylbenzidine (TMB) in the presence of H2O2. And interestingly, as the sample size reduces, the catalytic activity increases. At the same time, the electrochemical method to characterize the catalytic activity of Fe3O4 NPs using the response currents of the reaction product and substrate was also developed.
Fig. 1. TEM images of Fe3O4 NPs with different average diameters: (a) 11 nm, (b) 20 nm, (c) 150 nm.
Fig. 2. Size-dependent peroxidase-like catalytic activity of Fe3O4 NPs. (a) Time-dependent absorbance curves of the product in the absence (■) and presence of Fe3O4 NPs with average diameters of 11 (●), 20 (▲), and 150 nm (▼) under the optimized experimental conditions; (b) steady-state kinetic assay of Fe3O4 NPs with TMB as the substrate.
Fig. 3. Square-wave voltammetric behavior of reaction system without (a) and with (b) Fe3O4 NPs after different reaction time.
Fang Fang Peng, Yu Zhang , Ning Gu. Size -dependent peroxidase-like catalytic activity of Fe3O4 nanoparticles. Accepted by Chinese Chemical Letters 2008
