氧化石墨烯催化形成纳米钛酸锂颗粒的亲核反应机理研究  

Nucleophilic Formation Mechanism of Lithium Titanate Nanoparticles due to the Catalytic Reactivity of Graphene Oxide

作　　者：向宇 赵俊康 高胜基 翟飞越 张慧敏 张文峰 曹高萍 XIANG Yu;ZHAO Junkang;GAO Shengji;ZHAI Feiyue;ZHANG Huimin;ZHANG Wenfeng;CAO Gaoping(Institute of Chemical Defense,Academy of Military Sciences,Beijing 102205,China;Beijing Key Laboratory of Advanced Chemical Energy Storage Technology and Materials,Beijing 100191,China;Hebei University of Technology,Tianjin 300131,China;Beihang University,Beijing 100191,China)

机构地区：[1]军事科学院防化研究院,北京102205 [2]先进化学蓄电技术与材料北京市重点实验室,北京100191 [3]河北工业大学,天津300131 [4]北京航空航天大学,北京100191

出　　处：《防化研究》2023年第6期43-52,共10页CBRN DEFENSE

摘　　要：在用溶胶-凝胶法制备纳米尖晶石钛酸锂(Li_(4)Ti_(5)O_(12))颗粒的过程中,添加氧化石墨烯(GO)可更容易将其实现。本论文经密度泛函理论计算表明,在sp^(2)杂化碳原子层的供电子作用下,GO中的醛基、面内羟基和三元环氧基具有比水更强的亲核反应活性,能够优先于水同有机钛源发生反应,并原位形成纳米颗粒。X射线光电子能谱数据证实纳米颗粒与石墨烯片层之间通过强Ti-O-C化学键连接,表明纳米颗粒被“固定”在石墨烯片层上,从而显著抑制了高温烧结中的颗粒团聚效应,使纳米颗粒形貌得以保留。即使当石墨烯含量仅为3%时,得到的Li_(4)Ti_(5)O_(12)颗粒尺寸也小于50 nm。然而,对于用共沉淀法制备FePO_(4),GO却不能有助于获得均匀分散的纳米颗粒。这说明若要采用GO合成纳米复合材料,则必须考虑相关材料合成机理与GO的亲核活性是否匹配。Spinel Li_(4)Ti_(5)O_(12)nanoparticles can be easily produced with the addition of graphene oxide(GO)in the sol-gel process.In this work,density functional theory(DFT)calculations showed that under the electron donating effect of sp^(2)hybridization carbon atomic layer,the aldehyde,in-plane hydroxyl and ternary epoxy groups in GO had much stronger nucleophilic reactivity than water,and could react directly with the TBT to in-situ deposited nanoparticles.Xray photoelectron spectroscopy(XPS)data confirmed that these nanoparticles were bonded with graphene layers through strong Ti−O−C chemical bonds,indicating that the nanoparticles were“fixed”on graphene layers.The particle agglomeration effects in high temperature sintering were significantly inhibited,so that the nanoparticle morphology could be retained.It was demonstrated that the sizes of obtained Li_(4)Ti_(5)O_(12)particles were less than 50 nm even when the graphene content was only 3%.However,GO was not conducive to obtain uniformly dispersed nanoparticles in the process of preparing FePO_(4)via coprecipitation method.It was indicated that it was necessary to consider whether the material synthesis mechanism matches the nucleophilic activity of GO to synthesis relative graphene nanocomposites.

关 键 词：氧化石墨烯 亲核活性 溶胶-凝胶法 纳米颗粒 Li_(4)Ti_(5)O_(12) 

分 类 号：O647[理学—物理化学]