The enhanced photocatalytic performance toward carbamazepine by nitrogen-doped carbon dots decorated on BiOBr/CeO2: Mechanism insight and degradation pathways
The enhanced photocatalytic performance toward carbamazepine by nitrogen-doped carbon dots decorated on BiOBr/CeO2: Mechanism insight and degradation pathways
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DOI：
10.1016/j.cej.2019.123599
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发表时间：
2020-07-01
影响因子：
15.1
通讯作者：
Yang, Liwei
中科院分区：
文献类型：
--
作者：
Liang, Lanlan;Gao, Shengwang;Yang, Liwei
通过一种简单的方法成功地制备了新型的掺氮碳点(NCDS)修饰的BiOBR/CeO2。采用多种技术对光催化剂的形貌、结构、光学性能和光电化学性能进行了表征。通过对卡马西平(CBZ)在模拟太阳光照射下的降解来评价其光催化性能。在光照120min内，NCDS/BiOBR/CeO2对CBZ的降解率可达98%，远高于BiOBR或BiOBR/CeO2。CBZ降解的增强是由于NCDS的引入显著加速了紧密接触界面上光生载流子的迁移和分离。考察了光催化剂用量、CBZ初始浓度、初始pH、共存无机阴离子(Cl-、NO3-、SO42-)和天然有机物(NOM)、光照条件和水基质等关键操作参数对光催化降解效果的影响。在清除实验和电子自旋共振(ESR)的基础上，提出了电荷分离的光催化机理。采用LC/MS和三维激发发射基质荧光光谱(3DEMS)研究了CBZ的转化中间体和可能的降解途径。最后，该复合材料表现出良好的可回收性和稳定性。本研究为光催化剂的设计和水环境中难降解有机污染物的降解创造了新的机遇。
Novel nitrogen-doped carbon dots (NCDs) modified BiOBr/CeO2 was constructed successfully via a facile method. The morphology, structure, optical and photo-electrochemical properties of the photocatalysts were characterized by various technologies. The photocatalytic performance was evaluated by the degradation of carbamazepine (CBZ) under simulated solar light irradiation. The CBZ degradation by NCDs/BiOBr/CeO2 could achieve 98% within 120 min illumination, which was much higher than BiOBr or BiOBr/CeO2. The enhanced degradation of CBZ was due to the fact that the introduction of NCDs significantly accelerated the migration and separation of the photoinduced charge carries at the tightly contacted interface. The effects of some key operating parameters were further investigated, including photocatalyst dosage, initial CBZ concentration, initial pH, coexisting inorganic anions (Cl-, NO3-, SO42-) and natural organic matters (NOM), light irradiation conditions and water matrix. Basing on the scavenging experiments and electron spin resonance (ESR), the photocatalytic mechanism was proposed for the charge separation. Furthermore, the transformation intermediates and possible degradation pathway of CBZ were investigated by liquid chromatography coupled with mass spectrometry (LC/MS) and three-dimensional excitation-emission matrix fluorescence spectra (3D EEMs). Finally, the composite showed excellent recyclability and stability. This study created new opportunities for the design of photocatalysts and degradation of recalcitrant organic contaminants in aquatic environment.