Rational construct CQDs/BiOCOOH/uCN photocatalyst with excellent photocatalytic performance for degradation of sulfathiazole
Rational construct CQDs/BiOCOOH/uCN photocatalyst with excellent photocatalytic performance for degradation of sulfathiazole
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DOI：
10.1016/j.cej.2020.126541
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发表时间：
2021-01-15
影响因子：
15.1
通讯作者：
Wang, Zhaowei
中科院分区：
文献类型：
--
作者：
Hu, Zhongzheng;Xie, Xiaoyun;Wang, Zhaowei
设计了一种新型异质结光催化剂，即碳量子点修饰的BiOCOOH/超薄GC(3)N(4)纳米片(CQds/BiOCOOH/UCN)，其中碳量子点作为介体在BiOCOOH和超薄g-C3N4纳米片(UCN)之间传递电子。采用扫描电子显微镜、透射电子显微镜、X射线衍射仪、傅立叶变换红外光谱和X射线光电子能谱等手段对所制得的复合材料的物化性能进行了系统的表征。由50wt%的超薄g-C3N4纳米片(UCN)和4mLCQds溶液组成的4-CQds/BiOCOOH/UCN具有最佳的光催化活性。在LED灯照射90min后，4-CQDS/BiOCOOH/UCN对STZ的降解率达到99.28%+/-1.04，相应的矿化度为49.58%+/-1.36。4-CQds/BiOCOOH/UCN光催化性能的提高是由于光致发光(PL)、暂态光电流响应和电化学阻抗谱(EIS)测量揭示了光生电荷的快速转移和分离。通过自由基猝灭实验和电子自旋共振(ESR)分析，证明中心点O-2(-)和中心点OH是STZ降解的主要活性物种。此外，系统地考察了催化剂用量(0.2~1.2g/L)、pH值(3.0~11.0)、天然有机物和不同阴离子(Cl-、SO42-、NO3-)对4-CQDS/BiOCOOH/UCN复合材料光催化活性的影响。经高分辨质谱仪(HRMS)检测，共鉴定出17个主要中间体。最终，4-CQDS/BiOCOOH/UCN复合材料在回收实验中表现出良好的重复使用性能，并对去离子水(99.28%+/-1.04)、自来水(97.15%+/-1.16)、河水(96.44%+/-0.76)和污水处理厂出水(96.19%+/-1.20)显示出令人满意的降解能力。
The novel heterojunction photocatalysts also known as carbon quantum dots-decorated BiOCOOH/ultrathin gC(3)N(4) nanosheets (CQDs/BiOCOOH/uCN) were designed, where carbon quantum dots (CQDs) acted as mediators to shuttle electrons between BiOCOOH and ultrathin g-C3N4 nanosheets (uCN). The physicochemical properties of as-obtained composites were systematically characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The 4-CQDs/BiOCOOH/uCN consisting of 50 wt% ultrathin g-C3N4 nanosheets (uCN) and 4 mL CQDs solution manifested the optimal photoactivity. After 90 min of LED lamp irradiation, the STZ degradation efficiency by 4-CQDs/BiOCOOH/uCN reached 99.28% +/- 1.04, and the corresponding degree of mineralization was 49.58% +/- 1.36. The enhanced photocatalytic performance of 4-CQDs/BiOCOOH/uCN was owing to the fast photogenerated charges transfer and separation revealed by photoluminescence (PL), transient photocurrent responses and electrochemical impedance spectra (EIS) measurements. By means of the radicals quenching experiments and electron spin resonance spectroscopy (ESR) analysis, it was demonstrated that center dot O-2(-) and center dot OH were the dominant reactive species of STZ degradation. Besides, the effects of catalyst dosage (0.2-1.2 g/L), pH value (3.0-11.0), natural organic matter and different anions (Cl-, SO42-, NO3-) on the photocatalytic activity of 4-CQDs/BiOCOOH/uCN composite were systematically explored. 17 main intermediates were found based on high-resolution mass spectrometry (HRMS) detection. Eventually, the 4-CQDs/BiOCOOH/uCN composite showed favorable reusability in recycling experiments, and displayed satisfactory degradation abilities for STZ in deionized water (99.28% +/- 1.04), tap water (97.15% +/- 1.16), river water (96.44% +/- 0.76), and wastewater treatment plant effluent (96.19% +/- 1.20).