Abstract

Fe₃O₄/CeO₂/C-dot nanozyme as a hybrid nanocomposite was prepared and characterized. Fe₃O₄/CeO₂/C-dot nanocomposite presents horseradish peroxidase-like catalytic activity due to the presence of triple nanozymes in the nanocomposite. The kinetic parameters of nanozymatic assay present Michaelis–Menten behavior. A colorimetric assay for determination of H₂O₂ was introduced based on the catalytic activity of Fe₃O₄/CeO₂/C-dot nanocomposite in H₂O₂/TMB system. In the presence of nanozyme, H₂O₂ reduction occurs and TMB was oxidized to ox-TMB which causes a blue color in the system. In this manner, intensity of the blue color is dependent on H₂O₂ concentration. Also, Fe₃O₄/CeO₂/C-dot nanocomposite exhibits electrocatalytic activity toward H₂O₂ reduction. Multi-walled carbon nanotube/ionic liquid paste (MWIL) electrode was modified by Fe₃O₄/CeO₂/C-dot nanocomposite which reveals higher electrocatalytic activity toward hydrogen peroxide rather than Fe₃O₄/CeO₂ and Fe₃O₄/C-dot-modified electrodes. Catalytic and electrocatalytic determination of hydrogen peroxide shows the linear ranges of 1.0 × 10^–6–5.0 × 10^–13 M and 2.0 × 10^–8 to 1.0 × 10^–6 M, respectively.

Graphic abstract

中文翻译：

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Fe 3 O 4 / CeO 2 / C-点纳米复合材料的催化和电催化活性

摘要

制备并表征了Fe ₃ O ₄ / CeO ₂ / C点纳米酶为杂化纳米复合材料。Fe ₃ O ₄ / CeO ₂ / C点纳米复合材料由于在纳米复合材料中存在三重纳米酶而具有类似辣根过氧化物酶的催化活性。纳米酶测定的动力学参数呈现迈克尔尼斯-门腾行为。用于确定H的比色测定法₂ ö ₂是基于Fe的催化活性引入₃ ö ₄ /的CeO ₂ / C-点纳米复合物H中₂ ö ₂ / TMB体系。在纳米酶存在下，H ₂发生O ₂还原，TMB被氧化为ox-TMB，在系统中引起蓝色。以这种方式，蓝色的强度取决于H ₂ O ₂浓度。另外，Fe ₃ O ₄ / CeO ₂ / C点纳米复合材料表现出对H ₂ O ₂还原的电催化活性。Fe ₃ O ₄ / CeO ₂ / C点纳米复合材料修饰了多壁碳纳米管/离子液体糊（MWIL）电极，与Fe ₃ O ₄ / CeO ₂和Fe相比，其显示出更高的对过氧化氢的电催化活性。₃ O ₄ / C点修饰电极。催化和电催化测定过氧化氢的线性范围分别为1.0×10 ^–6 –5.0×10 ^–13  M和2.0×10 ^–8至1.0×10 ^–6M  。

图形摘要