A novel Ag2O/CeO2 heterojunction photocatalysts for photocatalytic degradation of enrofloxacin: possible degradation pathways, mineralization activity and an in depth mechanism insight
A novel Ag2O/CeO2 heterojunction photocatalysts for photocatalytic degradation of enrofloxacin: possible degradation pathways, mineralization activity and an in depth mechanism insight
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DOI：
10.1016/j.apcatb.2017.09.060
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发表时间：
2018-02-01
期刊：
影响因子：
--
通讯作者：
Zeng, Guang-Ming
中科院分区：
文献类型：
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作者：
Wen, Xiao-Ju;Niu, Cheng-Gang;Zeng, Guang-Ming
半导体光催化已被认为是最有前途的去除水溶液中抗生素的技术之一。在本研究中，通过原位加载Ag2CO3在CeO2主轴上，然后通过热分解过程制备Ag2O/CeO2 p-n异质光催化剂。Ag2O/CeO2复合材料在可见光照射下对恩诺沙星（EFA）的光催化活性增强。提出了一种可行的EFA降解途径。三维激发发射矩阵荧光光谱（3D EEMs）和总有机碳（TOC）分析表明，Ag2O/CeO2异质结光催化剂对EFA分子降解具有高矿化能力。瞬态光电流响应、PL谱和EIS表明，Ag2O/CeO2复合材料具有较高的光致电荷分离效率。活性物质捕获实验和ESR技术证实了h（+）和中心点O-2是参与有机污染物光降解的主要活性基团。结合各种性能表征和实验结果，提出了一种可能的光催化机理。此外，计算了Ag2O/CeO2异质结构的能带排列，为上述机理提供了有力的支持。本研究为构建新型异质结光催化剂提供了新的途径，并对异质结催化剂有了更深入的认识。
Semiconductor photocatalysis has been considered as one of the most promising technologies for the removal of antibiotics from aqueous solutions. In this study, Ag2O/CeO2 p-n heterojuction photocatalysts were fabricated by an in situ loading Ag2CO3 on CeO2 spindles and subsequent via a thermal decomposition process. The Ag2O/CeO2 composites exhibited enhanced photocatalytic activity for the photodegradation of enrofloxacin (EFA) under visible light irradiation. A plausible degradation pathway for EFA was proposed. The Ag2O/CeO2 heterojuction photocatalysts exhibited the high mineralization ability towards the EFA molecule degradation based on three-dimensional excitation emission matrix fluorescence spectroscopy (3D EEMs) and total organic carbon (TOC) analysis. Transient photocurrent response, PL spectrum and EIS indicate high photoinduced charge separation efficiency possess in Ag2O/CeO2 composites. Active species trapping experiments and ESR technique confirmed that h(+) and center dot O-2 were the main active groups involved in photo-degradation of organic pollutants. Through the combination of various performance characterization and experimental results, a possible photo catalytic mechanism was proposed. Moreover, the energy band alignments of Ag2O/CeO2 heterostructure were calculated, which provided strong support for the proposed mechanism. This work could provide a new approach to construct new heterojunction photocatalysts and a deeper insight for the heterojunction catalyst.