Enhanced visible light photocatalytic activity and oxidation ability of porous graphene-like g-C3N4 nanosheets via thermal exfoliation
Enhanced visible light photocatalytic activity and oxidation ability of porous graphene-like g-C3N4 nanosheets via thermal exfoliation
复制标题
通过热剥离增强多孔石墨烯类g-C3N4纳米片的可见光光催化活性和氧化能力
DOI：
10.1016/j.apsusc.2015.04.034
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发表时间：
2015-12-15
影响因子：
6.7
通讯作者：
Ho, Wing-Kei
中科院分区：
文献类型：
--
作者：
Dong, Fan;Li, Yuhan;Ho, Wing-Kei
通过硫脲直接热解然后热剥离的方法合成了类石墨烯多孔g - C3N4纳米片。随着剥离温度的升高，所得样品的颜色逐渐变浅，层的厚度和尺寸减小。提出了一种涉及逐层剥离和层分裂的形成机制。由于量子尺寸效应，g - C3N4纳米片的能带结构不断调整。时间分辨衰减光谱表明，电荷载流子的辐射寿命（71和72）从块状g - C3N4的4.13和26.23纳秒增加到类石墨烯g - C3N4纳米片的5.36和36.57纳秒。将g - C3N4纳米片样品应用于空气中NOx的可见光光催化去除。随着剥离温度从450℃升高到550℃，多孔g - C3N4纳米片的性能显著提高。此外，经过多次反应循环后，光化学和结构稳定性保持良好。通过监测反应中间体NO2，发现NO2的产生受到抑制。类石墨烯g - C3N4纳米片活性的提高主要归因于其独特电子结构导致的电荷载流子寿命延长和光氧化能力提高。由于高性能类石墨烯g - C3N4纳米片的合成方法简单，可以设想g - C3N4纳米片可应用于环境修复和太阳能转换。（C）2015爱思唯尔有限公司。保留所有权利。
Graphene-like porous g-C3N4 nanosheets were synthesized via direct pyrolysis of thiourea followed by a thermal exfoliation. With increased exfoliation temperature, the color of the resulting samples gradually became shallow, and the thickness and size of the layers were decreased. A formation mechanism involving layer-by-layer exfoliation coupled with layer splitting was proposed. The band structure of the g-C3N4 nanosheets was continuously tuned because of quantum size effect. Time-resolved decay spectra indicated that the radiative lifetime of charge carriers (71 and 72) increased from 4.13 and 26.23 ns for bulk g-C3N4 to 5.36 and 36.57 ns for graphene-like g-C3N4 nanosheets. The g-C3N4 nanosheet samples were applied for visible light photocatalytic removal of NOx in air. The performance of porous g-C3N4 nanosheets was significantly enhanced with increased exfoliation temperature from 450 to 550 degrees C. Moreover, photochemical and structural stability was well maintained after multiple reaction cycles. By monitoring the reaction intermediate NO2, it was found that the generation of NO2 was inhibited. The activity enhancement of graphene-like g-C3N4 nanosheets can be predominantly ascribed to the prolonged lifetime and improved photo-oxidation ability of charge carriers arising from the unique electronic structure. As the synthesis method for graphene-like g-C3N4 nanosheets with high a performance is simple, the g-C3N4 nanosheets can be envisioned to be applicable in environmental remediation and solar energy conversion. (C) 2015 Elsevier B.V. All rights reserved.