物理化学学报

所属专题: 光催化剂

最新录用    

Cu2+改性g-C3N4光催化剂的光催化性能

李小为, 王彬, 尹文轩, 狄俊, 夏杰祥, 朱文帅, 李华明   

  1. 江苏大学化学化工学院, 能源研究院, 江苏 镇江 212013
  • 收稿日期:2019-02-01 修回日期:2019-05-03 录用日期:2019-05-13 发布日期:2019-05-17
  • 通讯作者: 夏杰祥, 朱文帅 E-mail:xjx@ujs.edu.cn;zhuws@ujs.edu.cn
  • 基金资助:
    国家自然科学基金(21722604,21576122),中国博士后科学基金(2017M611726)和江苏省研究生科研与实践创新计划(SJKY19_2573)资助项目

Cu2+ Modified g-C3N4 Photocatalysts for Visible Light Photocatalytic Properties

LI Xiaowei, WANG Bin, YIN Wenxuan, DI Jun, XIA Jiexiang, ZHU Wenshuai, LI Huaming   

  1. School of Chemistry and Chemical Engineering, Institute for Energy Research, Jiangsu University, Zhenjiang 212013, Jiangsu Province, P. R. China
  • Received:2019-02-01 Revised:2019-05-03 Accepted:2019-05-13 Published:2019-05-17
  • Contact: XIA Jiexiang, ZHU Wenshuai E-mail:xjx@ujs.edu.cn;zhuws@ujs.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China (21722604, 21576122), Chinese Postdoctoral Science Foundation (2017M611726) and Postgraduate Research & Practice Innovation Program of Jiangsu Province, China (SJKY19_2573).

摘要: 本文通过将Cu2+掺入g-C3N4结构中成功制备了Cu/g-C3N4光催化剂,并进一步优化其光催化性能。同时,采用多种表征方法对Cu/g-C3N4光催化剂的结构、形貌、光学和光电性能进行了分析。X射线衍射(XRD)和X射线光电子能谱(XPS)结果表明制备的光催化剂为Cu/g-C3N4,且Cu的价态为+2。在可见光照射下,研究了不同铜含量的Cu/g-C3N4和g-C3N4光催化剂的光催化活性。实验结果表明,Cu/g-C3N4光催化剂的降解能力显著高于纯相的g-C3N4。N2吸附-解吸等温线表明,Cu2+的引入对g-C3N4的微观结构影响不大,说明光催化活性的提高可能与光生载流子的有效分离有关。因此,Cu/g-C3N4光催化降解RhB和CIP性能的提升可能是由于Cu2+可以作为电子捕获陷阱从而降低了载流子的复合速率。通过光电测试表明,在g-C3N4中掺入Cu2+可以降低g-C3N4的电子空穴复合速率,加速电子空穴对的分离,从而提高了其光催化活性。自由基捕获实验和电子自旋共振(ESR)结果表明,超氧自由基(O2·-)、羟基自由基(·OH)和空穴的协同作用提高了Cu/g-C3N4光催化剂的光催化活性。

关键词: Cu/g-C3N4, 光催化, 可见光, 活性物种, RhB, CIP

Abstract: Photocatalytic technology can effectively solve the problem of increasingly serious water pollution, the core of which is the design and synthesis of highly efficient photocatalytic materials. Semiconductor photocatalysts are currently the most widely used photocatalysts. Among these is graphitic carbon nitride (g-C3N4), which has great potential in environment management and the development of new energy owing to its low cost, easy availability, unique band structure, and good thermal stability. However, the photocatalytic activity of g-C3N4 remains low because of problems such as wide bandgap, weakly absorb visible light, and the high recombination rate of photogenerated carriers. Among various modification strategies, doping modification is an effective and simple method used to improve the photocatalytic performance of materials. In this work, Cu/g-C3N4 photocatalysts were successfully prepared by incorporating Cu2+ into g-C3N4 to further optimize photocatalytic performance. At the same time, the structure, morphology, and optical and photoelectric properties of Cu/g-C3N4 photocatalysts were analyzed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, UV-Vis diffuse reflectance spectroscopy (DRS), and photoelectric tests. XRD and XPS were used to ensure that the prepared photocatalysts were Cu/g-C3N4 and the valence state of Cu was in the form of Cu2+. Under visible light irradiation, the photocatalytic activity of Cu/g-C3N4 and pure g-C3N4 photocatalysts were investigated in terms of the degradation of RhB and CIP by comparing the amount of introduced copper ions. The experimental results showed that the degradation ability of Cu/g-C3N4 photocatalysts was stronger than that of pure g-C3N4. The N2 adsorption-desorption isotherms of g-C3N4 and Cu/g-C3N4 demonstrated that the introduction of copper had little effect on the microstructure of g-C3N4. The small difference in specific surface area indicates that the enhanced photocatalytic activity may be attributed to the effective separation of photogenerated carriers. Therefore, the enhanced photocatalytic degradation of RhB and CIP over Cu/g-C3N4 may be due to the reduction of carrier recombination rate by copper. The photoelectric test showed that the incorporation of Cu2+ into g-C3N4 could reduce the electron-hole recombination rate of g-C3N4 and accelerate the separation of electron-hole pairs, thus enhancing the photocatalytic activity of Cu/g-C3N4. Free radical trapping experiments and electron spin resonance indicated that the synergistic effect of superoxide radicals (O2·-), hydroxyl radicals (·OH) and holes could increase the photocatalytic activity of Cu/g-C3N4 materials.

Key words: Cu/g-C3N4, Photocatalytic, Visible light, Active species, RhB, CIP

MSC2000: 

  • O644