Magnetite ( $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 ) nanoparticles with different particle sizes (9.9–29.1 nm) were prepared by using the aerial oxidation method under light irradiation with various wavelengths at room temperature. The photocatalytic degradation of orange II using $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 nanoparticles as photocatalysts was evaluated. Experimental results showed that the particle sizes of $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 nanocrystals decreased gradually with the decreasing wavelengths of light irradiation. With the decrease in the size of the samples, the $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 nanoparticles exhibited a large surface area and high adsorption. Furthermore, the small-particle-sized $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 sample could cause an appropriate red shift of the spectra and promote the decomposition of $$\hbox {H}_{2}\hbox {O}_{2}$$ H 2 O 2 , and produce high-content $$^{\bullet }\hbox {OH}$$ ∙ OH radicals, which lead to an improvement of photodegradation efficiency of orange II.

中文翻译：

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可变尺寸磁铁矿纳米颗粒的光致合成及其对橙色 II 的光降解

使用光照下空气氧化法制备了不同粒径（9.9-29.1 nm）的磁铁矿（ $$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 ）纳米颗粒室温下各种波长的辐照。评价了使用$$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 纳米粒子作为光催化剂对橙色II的光催化降解。实验结果表明，随着光照射波长的减小，$$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 纳米晶的粒径逐渐减小。随着样品尺寸的减小，$$\hbox {Fe}_{3}\hbox {O}_{4}$$ Fe 3 O 4 纳米颗粒表现出较大的表面积和高吸附性。此外，