高等学校化学学报 ›› 2022, Vol. 43 ›› Issue (6): 20220105.doi: 10.7503/cjcu20220105

• 物理化学 • 上一篇    下一篇

Janus纳米金稳定的Pickering乳液界面催化氧化性能

王红, SAN Khin Nyein Ei, 方云(), 张鑫宇, 樊晔   

  1. 江南大学化学与材料工程学院, 合成与生物胶体教育部重点实验室, 无锡 214122
  • 收稿日期:2022-02-21 出版日期:2022-06-10 发布日期:2022-04-22
  • 通讯作者: 方云 E-mail:yunfang@126.com
  • 基金资助:
    国家自然科学基金(21606107);国家重点研发计划项目(2017YFB308705)

Pickering Emulsion Stabilization and Interfacial Catalytic Oxidation by Janus Nano-Au

WANG Hong, SAN Khin Nyein Ei, FANG Yun(), ZHANG Xinyu, FAN Ye   

  1. Key Laboratory of Synthetic and Biological Colloids,Ministry of Education,School of Chemical and Material Engineering,Jiangnan University,Wuxi 214122,China
  • Received:2022-02-21 Online:2022-06-10 Published:2022-04-22
  • Contact: FANG Yun E-mail:yunfang@126.com
  • Supported by:
    the National Natural Science Foundation of China(21606107);the National Key Research and Development Program of China(2017YFB0308705)

摘要:

Janus纳米粒子的结构设计和简易合成是Pickering乳液界面催化的关键. 本文通过在Pickering乳液保护法中操纵共轭亚油酸的自组装、 自交联性和弱还原性, 合成了Janus型自交联吸附胶束修饰的纳米Fe3O4 (SCA-Fe3O4), 并在其表面原位还原金后, 合成了Janus型催化剂Au-SCA-Fe3O4, 考察其同时作为乳化剂和催化剂在乳液界面催化苯甲醇氧化生成苯甲醛的性能. 结果表明, 该Janus纳米粒子的金修饰量(质量分数)仅为0.66%, 兼具乳化性、 催化性和磁响应性. Au-SCA-Fe3O4可制备外观稳定(100 μm)和热稳定(90 ℃)的苯甲醇/水型Pickering乳液, 可显著提高互不相溶反应物与催化剂间的接触面积, 使其催化活性达到均匀纳米催化剂的2倍和非乳液催化时的3倍, 其在界面的不可转动性使苯甲醛的选择性高于99.9%, 避免了苯甲醛被过度氧化成苯甲酸.

关键词: Janus纳米粒子, 金, 界面催化, Pickering乳液, 共轭亚油酸, 纳米四氧化三铁

Abstract:

Structural design and facile synthesis of Janus nanoparticles are crucial to Pickering emulsion interfacial catalysis. By manipulating self-assembly and self-crosslinking activities and weak reducibility of conjugated linoleic acid(CLA), Janus self-crosslinked admicelle-decorated nano-Fe3O4(SCA-Fe3O4) was synthesized under protection by Pickering emulsions, and then Janus nano-Au catalyst(Au-SCA-Fe3O4) was prepared by in-situ reduction of Au on the particle surface. Subsequently, Au-SCA-Fe3O4 was investigated to act as both emulsifier and catalyst in the emulsion interfacial catalytic oxidation of benzyl alcohol to benzaldehyde. Experimental results show that Au-SCA-Fe3O4 is only with 0.66%(mass fraction) of Au content, but shows emulsifying, catalytic activities and magnetic response simultaneously. It creates a Pickering emulsion with appearance stability(uniform size of about 100 μm) and thermal stability(up to 90 ℃), and improves the catalytic activity to be two fold of the fully-modified counterpart and three times as high as the coarse dispersion, which is ascribed to significantly increased contact between insoluble reactants and the catalyst. Moreover, the selectivity of benzaldehyde is higher than 99.9%, which depends on the non-rotational property of Au-SCA-Fe3O4 at the benzyl alcohol/water interface avoiding the excessive oxidation of benzaldehyde into benzoic acid. It would offer a new approach for green synthesis and application of Janus nano-catalysts.

Key words: Janus nanoparticles, Au, Interfacial catalysis, Pickering emulsion, Conjugated linoleic acid, Nano-Fe3O4

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