Zhang Menglu, Yang Yu, An Xiaoqiang, Zhao Jingjing, Bao Yueping, Hou Li-An
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing 100875, China.
J Hazard Mater. 2022 Feb 15;424(Pt B):127424. doi: 10.1016/j.jhazmat.2021.127424. Epub 2021 Oct 3.
Exfoliation of carbon nitride (g-CN) into an ultrathin nanostructure significantly improves its photoactivity. However, the effects of the exfoliation method on the microstructure and photocatalytic performance of g-CN nanosheets remain largely unknown. Herein, several typical strategies, such as thermal, chemical, ultrasonic and one-step exfoliation, were applied to exfoliate g-CN nanosheets for photocatalytic applications. A procedure capable of controlling the morphology, microstructure, light-absorption property, and visible light photoactivity of g-CN nanosheets was attempted. We found that nanosheets prepared from one-step exfoliation present superior photocatalytic efficiency under visible light than those fabricated by thermal exfoliation and ultrasonic exfoliation. The kinetic constants for bisphenol A (BPA) photodegradation over these samples were determined to be 6.5, 4.5 and 2.3 times higher than bulk g-CN, respectively. For chemical exfoliation, excessive oxidation by HSO can lead to the structural defects and deactivation of urea-derived g-CN nanosheets. Carbon nitride nanosheets synthesized by one-step exfoliation exhibited high specific surface area, optimal band gap energy structure, and high charge separation efficiency, thereby increasing visible-light photoactivity. Enabling cost-effective production of ultrathin and robust g-CN nanosheets, one-step exfoliation offers a potential strategy to exploit high-performance g-CN for water purification applications.
将氮化碳（g-CN）剥离成超薄纳米结构可显著提高其光活性。然而，剥离方法对g-CN纳米片微观结构和光催化性能的影响在很大程度上仍不清楚。在此，采用了几种典型策略，如热剥离、化学剥离、超声剥离和一步剥离，来剥离g-CN纳米片用于光催化应用。尝试了一种能够控制g-CN纳米片的形态、微观结构、光吸收特性和可见光光活性的方法。我们发现，一步剥离制备的纳米片在可见光下的光催化效率优于热剥离和超声剥离制备的纳米片。这些样品上双酚A（BPA）光降解的动力学常数分别比块状g-CN高6.5倍、4.5倍和2.3倍。对于化学剥离，HSO的过度氧化会导致尿素衍生的g-CN纳米片的结构缺陷和失活。一步剥离合成的氮化碳纳米片具有高比表面积、最佳带隙能量结构和高电荷分离效率，从而提高了可见光光活性。一步剥离能够经济高效地生产超薄且坚固的g-CN纳米片，为开发用于水净化应用的高性能g-CN提供了一种潜在策略。
