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伴随环境污染问题日益加剧,借助半导体材料实现光能的光电转化在催化及环境领域引起广泛关注。本文借助电化学方法快速高效地合成不同沉积时间纳米赤铁矿薄膜电极。X射线衍射(XRD)、Raman光谱测试表明其成分为赤铁矿物相;原子力显微镜(AFM)观测颗粒尺寸约52.1(±1.48)nm×50.5(±1.49)nm,表面高度起伏分布于70~100 nm,且分布特征符合正态分布规律。紫外可见漫反射吸收谱显示电极可显著吸收350~600 nm波长范围可见光,计算得禁带宽度约2.0~2.1 e V。光电化学实验光电流密度-时间曲线及电流-电压曲线表明电极有良好的可见光光电催化活性,且反应符合Langmuir-Hinshelwood多相反应动力学模型。进一步选取效果较显著的沉积时间10 min电极研究其光电催化降解苯酚活性,0.65 V vs.SCE(饱和甘汞电极)恒电势光照条件下6 h苯酚降解率达62%,拟合一级动力学反应模型可知,反应速率常数k为0.16 h-1(R2=0.996)。综上,本文研究结果显示电化学法简单高效合成的纳米赤铁矿具有良好半导体性能且能够可见光光电催化降解苯酚等有机污染物。
With the increasing environmental pollution, the use of semiconductor materials to achieve the photoelectric conversion of light energy in the field of catalysis and the environment caused widespread concern. In this paper, the rapid and efficient synthesis of nano-hematite thin-film electrodes with different deposition time by electrochemical method. X-ray diffraction (XRD) and Raman spectrum showed that the composition was hematite. The particle size of AFM was about 52.1 (± 1.48) nm × 50.5 (± 1.49) nm and the surface height was about 70 ~ 100 nm, and the distribution features are in accordance with the normal distribution. UV-visible diffuse reflectance absorption spectrum shows that the electrode can significantly absorb the visible light in the wavelength range of 350-600 nm, and the calculated bandgap is about 2.0-2.1 eV. Photoelectrochemical experiments Photocurrent density-time curve and current-voltage curve showed that the electrode has good visible light photo-catalytic activity, and the reaction is in accordance with the Langmuir-Hinshelwood multiphase reaction kinetic model. Furthermore, the photocatalytic degradation of phenol was further studied with 10 min deposition time, and the degradation rate of phenol was 62% at 6 h after 0.65 V vs.SCE (saturated calomel electrode) potentiostatic light irradiation. The fitted first-order kinetics The reaction model shows that the reaction rate constant k is 0.16 h-1 (R2 = 0.996). In summary, the results of this study show that the electrochemical simple and efficient synthesis of nano-hematite has good semiconductor properties and can be visible light photo-catalytic degradation of organic pollutants such as phenol.