化学学报 ›› 2022, Vol. 80 ›› Issue (10): 1385-1393.DOI: 10.6023/A22060266 上一篇    下一篇

研究论文

Ag/AgCl/ZIF-8复合材料的制备及其对NO光催化氧化性能的研究

朱鹏飞*(), 娄晨思, 史雨翰, 王传义*()   

  1. 陕西科技大学环境科学与工程学院 西安 710021
  • 投稿日期:2022-06-19 发布日期:2022-08-31
  • 通讯作者: 朱鹏飞, 王传义
  • 基金资助:
    国家自然科学基金(22006097); 陕西省重点研发计划项目(2022SF-250)

Study on Preparation of Ag/AgCl/ZIF-8 Composite and Photocatalytic NO Oxidation Performance

Pengfei Zhu(), Chensi Lou, Yuhan Shi, Chuanyi Wang()   

  1. School of Environmental Science and Engineering, Shaanxi University of Science and Technology, Xi'an 710021, China
  • Received:2022-06-19 Published:2022-08-31
  • Contact: Pengfei Zhu, Chuanyi Wang
  • Supported by:
    National Natural Science Foundation of China(22006097); Key Research and Development Program of Shaanxi Province(2022SF-250)

采用室温沉淀法合成菱形十二面体晶体结构ZIF-8(一种Zn金属有机框架材料), 然后通过光还原沉积法将Ag/AgCl纳米颗粒沉积于ZIF-8表面, 得到Ag/AgCl/ZIF-8复合光催化剂, 通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积测试法(BET)、紫外-可见漫反射吸收光谱(UV-Vis DRS)等一系列表征手段对其晶体结构、形貌、比表面积及吸光性能等进行了表征. 以低浓度NO作为目标去除污染物, 系统研究了Ag/AgCl/ZIF-8复合材料对NO的可见光催化氧化性能, 并对其反应机理进行了深入分析. 结果表明: (1) Ag/AgCl/ZIF-8复合材料中Ag0表面等离子体共振(SPR)效应增强了可见光的吸收; (2) ZIF-8具有大的比表面积, 使其能富集更多的氧分子和NO分子, 促进生成超氧自由基和NO光催化氧化; (3) 复合材料中光生空穴能够转移到AgCl的表面氧化Cl-为Cl0, Cl0具有强氧化性, 一方面促进了NO光催化氧化, 另一方面有效抑制了光生电子-空穴的复合, 提高了催化剂的稳定性.

关键词: 氮氧化物, 光催化氧化, 金属有机框架材料, ZIF-8复合材料

ZIF-8, a subclass of metal-organic frameworks with Zn2+ and 2-methylimidazole, featuring high special surface area and easily adjustable structures have exhibit great application potential in photocatalytic reaction. However, ZIF-8 often suffers from short light harvesting range and rapid recombination of photogenerated carriers, resulting in poorer catalytic activity. Here, ZIF-8 was synthesized by a precipitation method, and then Ag/AgCl nanoparticles were deposited on the surface of ZIF-8 by photo-deposition to obtain Ag/AgCl/ZIF-8 composite. The typical synthesis procedure is as follows: 0.2 g of ZIF-8 powder was dispersed in 50 mL of methanol and sonicated for 30 min to make it uniformly dispersed, then 0.1699 g of AgNO3 (1 mmol) and 0.045 g ZnCl2 were added to the above solution, which was placed on a magnetic stirrer and stirred in the dark for 30 min, followed irradiating it under light for 10 min. The obtained sample was washed several times with methanol and dried under a freeze-drying oven for 12 h. The crystal structure, morphology, specific surface area and light absorption properties were characterized by using X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), specific surface area test method (BET) and UV-Vis diffuse reflection absorption spectra (UV-Vis DRS), respectively. Finally, the photocatalytic oxidation performance of Ag/AgCl/ZIF-8 for NO removal under visible light was systematically studied, and its reaction mechanism was further analyzed. Thus, the resulting Ag/AgCl/ZIF-8 composite showed enhanced NO photocatalytic removal performance, reaching the highest NO removal of 43.5% under 35 min visible light irradiation and better stability compared with the parent ZIF-8. The above results show that: (1) Ag0 surface plasmon resonance (SPR) effect in Ag/AgCl/ZIF-8 composite enhances the absorption of visible light; (2) ZIF-8 can enrich more oxygen molecules and NO molecules, promoting the formation of superoxide free radicals and NO photocatalytic oxidation performance with a large specific surface area; (3) the photogenerated holes in the composite can be transferred to the surface of AgCl to oxidate Cl- to Cl0, which possess more strong oxidation ability for improving the photocatalytic oxidation of NO. On the other hand, it effectively inhibits the recombination of photogenerated electrons and holes, which improves the stability of the catalyst.

Key words: nitrogen oxides, photocatalytic oxidation, metal organic framework materials, ZIF-8 composite