Flower-like g-C3N4 assembly from holy nanosheets with nitrogen vacancies for efficient NO abatement
Flower-like g-C3N4 assembly from holy nanosheets with nitrogen vacancies for efficient NO abatement
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由具有氮空位的神圣纳米片组装而成的花状 g-C3N4 可有效去除 NO
DOI：
10.1016/j.apsusc.2019.06.125
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发表时间：
2019-10-30
影响因子：
6.7
通讯作者：
Liu, Yi
中科院分区：
文献类型：
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作者：
Duan, Youyu;Li, Xiaofang;Liu, Yi
由于石墨氮化碳（gCN）只能吸收波长< 450 nm的可见光，且光生载流子的复合速度快，因此具有中等的光反应性。本文利用三聚氰胺-三聚氰酸（MCA）超分子聚集体在500℃下煅烧制备了具有氮空位的多孔纳米片的花状gCN组装体，并使用可见光LED灯（λ >= 400 nm）作为光源，在连续流反应器中使用NO氧化来评价所制备的gCN的光反应性。系统地研究了煅烧时间（2 ~ 14 h）对制备的花状gCN结构、性能及光催化性能的影响。随着煅烧时间的延长，花状gCN的可见光反应性增强，其中焙烧10 h的样品（F10样品）的NO去除率最高（59.7%），远高于在相同温度下煅烧10 h的块体gCN （45.8%， B10样品）。花状gCN的光催化活性提高主要归因于pi-pi层的凝聚堆积，面内氢键的断裂，增加了BET的表面积，并形成了氮空位，从而扩大了可见光响应范围，改善了光生载流子的分离。
As graphitic carbon nitride (gCN) can only absorb visible light with wavelength < 450 nm, and the recombination of photo-generated carriers is quick, resulting in its moderate photoreactivity. Herein, flower-like gCN assembly from porous nanosheets with nitrogen vacancies was prepared by calcination of melamine-cyanuric acid (MCA) supramolecular aggregates at 500 degrees C. NO oxidation was used to evaluate the photoreactivity of the prepared gCN in a continuous-flow reactor using a visible LED lamp (lambda >= 400 nm) as the light source. We systematically studied the effect of calcination time (2-14 h) on the structure, property and photocatalytic performance of the prepared flower-like gCN. Enhanced visible photoreactivity of flower-like gCN was observed with extension the calcination time, and the sample calcined for 10 h (F10 sample) exhibits the highest NO removal rate (59.7%), which is much higher than that of bulk gCN (45.8%, B10 sample) which was prepared by calcination of melamine at the same temperature for 10 h. The improved photocatalytic activity of flower-like gCN is ascribed to the condensed pi-pi layer stacking, breaking of intraplanar hydrogen bonds, enlarged BET surface area, and formation of nitrogen vacancies, which result in a broadened visible responsive range and improved separation of the photo-generated carriers.