高效可回收AX2型Fe3O4-mSiO2-Au纳米复合催化剂的制备及其性能  

Preparation and performance of high-efficient and recyclable AX-Type FeO-mSiO-Au nanocomposite catalyst

作　　者：王志强 韩伟昌 张成宇 祝强韬 戚栋明[1] 孙阳艺[1] WANG Zhiqiang;HAN Weichang;ZHANG Chengyu;ZHU Qiangtao;QI Dongming;SUN Yangyi(College of Textile Science and Engineering(International Institute of Silk),Zhejiang Sci-Tech University,Hangzhou 310018,China)

机构地区：[1]浙江理工大学纺织科学与工程学院(国际丝绸学院),杭州310018

出　　处：《浙江理工大学学报（自然科学版）》2020年第6期797-805,共9页Journal of Zhejiang Sci-Tech University(Natural Sciences)

基　　金：国家自然科学基金青年基金项目(51703203);浙江省新苗人才计划项目(2019R406001)。

摘　　要：为制备一种催化性能优良的磁性介孔二氧化硅载Au复合催化剂,采用溶胶-凝胶法,利用硅源前驱体在Fe3O4种子粒子上的异相成核与生长,制备了一种AX2型胶体分子结构的Fe3O4-mSiO2载体材料,并继续负载Au后得到复合催化剂。通过TEM、BET、FI-IR、XRD对所得复合催化剂的形貌和结构组成进行表征和分析。结果表明:通过调控氨水的用量,可得到AX2型Fe3O4-mSiO2载体材料,其具有大的比表面积和良好的介孔孔道结构,可均匀负载Au NPs得到复合催化剂。在还原剂NaBH4存在下,将该复合催化剂用于催化罗丹明B(RhB)、4-硝基苯酚(4-NP)的还原反应,表现出良好的催化活性(5 min内将RhB分子100%转换为leuco分子形式)、有效的循环利用性(高达7次)和高稳定性,且RhB和4-NP的催化一级动力学常数分别为0.67 min^-1和0.32 min^-1。复合催化剂表面上均匀稳定分布有Au NPs,其存在的介孔孔道结构可将吸附的RhB、4-NP分子更好的与Au NPs活性位点接触,促进电子转移,从而提高了还原反应速率。该研究为设计新型高比表面积可回收催化剂载体材料提供了一种有效途径。In order to prepare an Au-loaded magnetic mesoporous silica composite catalyst with excellent catalytic performance, a Fe3O4-mSiO2 carrier material with AX2-type colloidal molecular structure was synthesized based on a sol-gel method by controlling the heterogeneous nucleation and growth of silicon precursors on the Fe3O4 seed particles. After loading Au nanoparticles, the nanocomposite catalysts were successfully obtained. The morphology, structure and composition of the composite catalyst were characterized and analyzed by TEM, BET, FT-IR and XRD. The results showed that the AX2-type Fe3O4-mSiO2carrier material could be obtained by adjusting the amount of ammonia water, with a large specific surface area and a good mesoporous channel structure, and thus they could uniformly load with Au NPs to obtain the composite catalysis. These catalysts were used for reduction reaction of rhodamine B(RhB) and 4-nitrophenol(4-NP) in the presence of NaBH4 reducing agent and showed excellent catalytic activity(100% conversion of RhB molecules to leuco molecule form within 5 min), efficient recyclability(up to 7 cycles) and high stability. And the first-order kinetic constants(k) of RhB and 4-NP reduction were 0.67 min^-1 and 0.32 min^-1, respectively. Au NPs were evenly distributed on the surface of the composite catalysis, and the mesoporous channel structure could adsorb RhB and 4-NP molecules to better contact with the active site of Au NPs so as to promote the electron transfer and thus improve the reduction reaction rate. AX2-type Fe3O4-mSiO2prepared in this study provides an effective way for the design of recyclable catalyst carrier materials with a high specific surface area.

关 键 词：AX2型胶体分子 磁性 介孔氧化硅 Au纳米粒子(Au NPs) 催化剂 

分 类 号：O643.36[理学—物理化学]