A Strategy of Enhancing the Photoactivity of g-C3N4 via Doping of Nonmetal Elements: A First-Principles Study

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• 作者：Xinguo Ma ; Yanhui Lv ; Jing Xu ; Yanfang Liu ; Ruiqin Zhang ; Yongfa Zhu
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：November 8, 2012
• 年：2012
• 卷：116
• 期：44
• 页码：23485-23493
• 全文大小：602K
• 年卷期：v.116,no.44(November 8, 2012)
• ISSN：1932-7455

文摘

An effective structural doping approach has been described to modify the photoelectrochemical properties of g-C₃N₄ by doping with nonmetal (sulfur or phosphorus) impurities. Here, the substitutional and interstitial doped models of g-C₃N₄ systems were constructed with different doped sites, and then their dopant formation energies and electronic properties were performed to study the stability and visible-light photoactivity using first-principles density functional theory, respectively. Our results have identified that an S atom preferentially substitutes for the edge N atom of g-C₃N₄; however, a P atom preferentially situates the interstitial sites of in-planar of g-C₃N₄. Furthermore, it is demonstrated that the doping with nonmetal impurities reduces the energy gap to enhance the visible-light absorption of g-C₃N₄. The increased dispersion of the contour distribution of the HOMO and LUMO brought by doping facilitates the enhancement of the carrier mobility, while the noncoplanar HOMO and LUMO favor the separation of photogenerated electron鈥揾ole pairs. Especially, P interstitial doping shows a prominent potential due to the appearance of a new channel for carrier migration. It should be pointed out that the proper doping form should be controlled, so that reasonable photoelectrochemical properties can be achieved.