物理化学学报 >> 2015, Vol. 31 >> Issue (8): 1549-1558.doi: 10.3866/PKU.WHXB201506021

催化和表面科学 上一篇    下一篇

结构型载体负载纳米银合成及催化性能

赵甲,刘立峰,张颖()   

  • 收稿日期:2015-02-16 发布日期:2015-08-12
  • 基金资助:
    国家自然科学基金(21173141);陕西省工业攻关项目(2011K08-14);教育部长江学者和创新团队发展计划滚动支持项目(IRT-14R33)

Synthesis of Silver Nanoparticles Loaded onto a Structural Support and Their Catalytic Activity

Jia. ZHAO,Li-Feng. LIU,Ying. ZHANG()   

  • Received:2015-02-16 Published:2015-08-12
  • Supported by:
    the National Natural Science Foundation of China(21173141);Key Industry Project of Shaanxi Province of China(2011K08-14);Changjiang Scholars and Innovative Research Team in University of Ministry of Education, China(IRT-14R33)

摘要:

通过两步聚合法合成具有温度敏感性能的核-壳型聚(苯乙烯-N-异丙基丙烯酰胺)/N-异丙基丙烯酰胺共聚3-(甲基丙烯酰氧)丙基三甲氧基硅烷(P(St-NIPAM)/P(NIPAM-co-MPTMS))复合微凝胶材料.以经3-巯丙基-三甲氧基硅烷(MPS)表面修饰的复合微凝胶为载体,乙醇为还原剂,在温和条件下控制性还原制备纳米银微粒.通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外(FT-IR)光谱仪、X-射线光电子能谱(XPS)、X射线衍射(XRD)仪、热分析(TGA)和紫外-可见(UV-Vis)分光光度计等手段对P(St-NIPAM)/P(NIPAM-co-MPTMS)-(SH)Ag复合微凝胶的结构、组成和性质进行表征.同时,以硼氢化钠还原对硝基苯酚为模型反应,对该复合材料催化还原性能进行了评价.结果表明,载体含有巯基的有机-无机杂化网络结构的限域作用使原位合成的纳米银微粒的分散性较好.载体微凝胶壳层链节中无机组分MPTMS的引入在一定程度上降低了复合凝胶温敏性,但复合凝胶仍表现出催化还原反应的温敏性调控和良好的催化活性.以上实验结果与温敏性PNIPAM链节被无机网络分隔而有利于反应传质及壳层巯基对原位纳米银形成尺寸和空间分布的有效控制有关.本研究对功能性金属纳米催化复合材料的研究具有积极借鉴意义.

关键词: 有机-无机复合微凝胶, 温敏性, 负载催化剂, 纳米银, 对硝基苯酚还原

Abstract:

The core-shell type poly(styrene-N-isopropylacrylamide)/poly(N-isopropylacrylamide-co-3-methacryloxypropyltrimethoxysilane) (P(St-NIPAM)/P(NIPAM-co-MPTMS)) composite microgels with thermosensitivity were synthesized by two-step polymerization methods. Using P(St-NIPAM)/P(NIPAM-co-MPTMS) composite microgels modified by (3-mercaptopropyl) trimethoxysilane (MPS) as support material, Ag nanoparticles (AgNPs) were in-situ controllably synthesized using ethanol as a reducing regent. The structure, composition and properties of the prepared P(St-NIPAM)/P(NIPAM-co-MPTMS)-(SH)Ag composite materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fouriertransform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and UV-visible spectroscopy (UV-Vis). Additionally, the catalytic activity of the composite microgels was investigated using the reduction of 4-nitrophenol (4-NP) by NaBH4 as a model reaction. The results showed that the dispersity of the in situ formed AgNPs was greatly improved because of the confining effect of the organic-inorganic microgel network with mercapto groups. Although the thermosensitivity of the composite microgels decreased because of the PNIPAM segments separated by the inorganic networks formed by MPTMS, the composite microgels still showed excellent catalytic performance and thermosensitivity in modulating the catalytic activity of AgNPs. These findings are related to the following aspects. The separated PNIPAM segments are favorable for mass transfer, and the networks with mercapto groups allow control of the size and local distribution of the in situ formed AgNPs. The present results are significant for construction of functional nanoscale metal catalytic materials.

Key words: Organic-inorganic hybrid microgel, Thermo-sensitivity, Supported catalyst, Silver nanoparticles, 4-Nitrophenol reduction

MSC2000: 

  • O643