Visible-Light-Responsive Graphitic Carbon Nitride: Rational Design and Photocatalytic Applications for Water Treatment
Visible-Light-Responsive Graphitic Carbon Nitride: Rational Design and Photocatalytic Applications for Water Treatment
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DOI：
10.1021/acs.est.6b02579
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发表时间：
2016-12-06
影响因子：
11.4
通讯作者：
Shuai, Danmeng
中科院分区：
文献类型：
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作者：
Zheng, Qinmin;Durkin, David P.;Shuai, Danmeng
石墨碳氮化物（g-C3 N4）最近出现作为一个有前途的可见光响应聚合物光催化剂;然而，分子水平的理解材料的性能和其应用于水净化的探索不足。在本研究中，我们合理地设计了非金属掺杂的超分子基g-C3 N4，其具有改善的表面积和电荷分离。密度泛函理论（DFT）模拟表明，碳掺杂的g-C3 N4显示出一个化学稳定的结构，促进电荷分离，并具有合适的导带和价带的光催化氧化相比，磷掺杂的g-C3 N4的能级。优化的碳掺杂，超分子为基础的g-C3 N4表现出2.3-10.5倍的苯酚和持久性有机微污染物的降解的反应速率增强相比，传统的，三聚氰胺为基础的g-C3 N4在模型缓冲系统在模拟可见光照射下。碳掺杂，而不是磷掺杂的污染物降解的反应性与DFT模拟结果一致。在g-C3 N4上观察到选择性污染物降解，这可能是由于不同g-C3 N4样品上的活性氧物质产生和/或污染物-光催化剂界面相互作用的差异。此外，g-C3 N4是一种强大的光催化剂，用于天然原水和（部分）处理水和废水中的污染物降解。总之，DFT模拟是预测光催化剂特性和污染物去除氧化性能的可行工具，它们指导可见光响应g-C3 N4的合理设计，制造和实施，以实现高效，稳健和可持续的水处理。
Graphitic carbon nitride (g-C3N4) has recently emerged as a promising visible-light-responsive polymeric photocatalyst; however, a molecular-level understanding of material properties and its application for water purification were underexplored. In this study, we rationally designed nonmetal doped, supramolecule-based g-C3N4 with improved surface area and charge separation. Density functional theory (DFT) simulations indicated that carbon-doped g-C3N4 showed a thermodynamically stable structure, promoted charge separation, and had suitable energy levels of conduction and valence bands for photocatalytic oxidation compared to phosphorus-doped g-C3N4. The optimized carbon-doped, supramoleculebased g-C3N4 showed a reaction rate enhancement of 2.3-10.5-fold for the degradation of phenol and persistent organic micropollutants compared to that of conventional, melamine-based g-C3N4 in a model buffer system under the irradiation of simulated visible sunlight. Carbon-doping but not phosphorus-doping improved reactivity for contaminant degradation in agreement with DFT simulation results. Selective contaminant degradation was observed on g-C3N4, likely due to differences in reactive oxygen species production and/or contaminant-photocatalyst interfacial interactions on different g-C3N4 samples. Moreover, g-C3N4 is a robust photocatalyst for contaminant degradation in raw natural water and (partially) treated water and wastewater. In summary, DFT simulations are a viable tool to predict photocatalyst properties and oxidation performance for contaminant removal, and they guide the rational design, fabrication, and implementation of visible-light-responsive g-C3N4 for efficient, robust, and sustainable water treatment.