利用无机原料水热合成法制备BiOI/BiOBr复合可见光催化剂,通过XRD、SEM、EDS、DRS、I-t响应曲线等手段对催化剂的物相组成和光化学性能进行了系统表征.以RhB为目标污染物,考察了催化剂的光催化活性并对最优比例催化剂的稳定性进行评价,通过ESR分析和自由基捕获实验探究了RhB的光催化降解机制.研究结果表明:无机原料水热合成法可成功制备纯度高、结晶性能良好的BiOI/BiOBr复合可见光催化剂;BiOI的复合降低了BiOBr光催化剂的电子-空穴的复合,拓宽其可见光响应范围,提高了光催化降解活性,其中质量比为8%的BiOI/BiOBr活性最佳,可见光照21 min后RhB的脱色率可达100%,是纯BiOBr的1.50倍,且重复使用5次后仍具有较高的光催化活性;复合催化剂光催化降解RhB的过程中,参与降解的主要活性物种为空穴(h+)和超氧自由基(·O-2).%BiOI/BiOBr composite visible photocatalyst was prepared via hydrothermal method using inorganic materials, and characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-Ray spectroscopy, UV-vis diffuse reflectance spectra and transient photocurrent response curve for the phase composition and optical property.Taking rhodamine B (RhB) as the target pollutant, the photocatalytic activity and stability of photocatalysts were studied under visible light irradiation.Furthermore, the mechanism in the process of photocatalytic degradation was discussed by electron spin resonance spectroscopy analysis and the trapping experiment of generated radicals.The results show that BiOI/BiOBr composite photocatalyst prepared by hydrothermal method using inorganic materials own high purity and excellent crystallization performance.Composited by BiOI, BiOBr exhibits higher photocatalytic activity considerably by reducing the rate of electron-hole recombination and broadening the range of visible-light response.Among the prepared composites with various BiOI contents, 8% BiOI/BiOBr exhibits the best efficiency in the degradation of RhB.After irradiation for 21 min, the degradation rate of RhB is 100%, which is 1.5 times of pure BiOBr.After 5 times recycle, it also shows high photocatalytic activity.The results also suggest that holes and ·O-2 are the main reactive species in the photocatalytic process of the RhB degradation.
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