金属有机骨架/石墨烯复合气凝胶微球的制备

Preparation of Metal Organic Frameworks/Graphene Aerogel Microspheres

为提高金属有机骨架材料ZIF-8(Zn(Hmim)_(2),Hmim=2-甲基咪唑)的性能及扩展其应用范围,以石墨烯气凝胶微球(rGOAM)为载体,将ZIF-8均匀负载于石墨烯片层上,制得ZIF-8/石墨烯复合气凝胶微球(ZIF/rGOAM)。首先通过静电喷雾结合热/微波还原得到2种多孔、疏水的rGOAM,然后采用原位生长的方法,在水溶液中使ZIF-8于石墨烯微球的片层原位生成,得到ZIF/rGOAM。通过表征2种不同还原方式得到的ZIF/rGOAM,结果表明ZIF-8能够均匀紧密地负载到石墨烯气凝胶微球上。而相比于微波还原,热还原的石墨烯气凝胶微球的还原程度更低,具有更多含氧基团,能够固定更高含量的金属离子,因此ZIF-8的负载量更高,得到具有更好性能的复合气凝胶微球。所得ZIF/rGOAM由于气凝胶微球的多孔性,提高了ZIF-8的利用率,在气体吸附、电极材料等方面具有很大的应用潜力。

In order to improve the performance of metal organic framework material ZIF-8(Zn(Hmim)2,Hmim=2-methylimidazole)and expand its application range,the graphene aerogel microspheres(rGOAM)were used as carrier,and ZIF-8 nanocrystals were uniformly loaded on the graphene sheets to prepare ZIF-8/graphene aerogel microsphere composites(ZIF/rGOAM).Firstly,two porous,hydrophobic rGOAMs were obtained by electrostatic spraying combined with the heat/microwave reduction.Then ZIF-8 was generated on the sheets of graphene microspheres in an aqueous solution to obtain ZIF/rGOAM by in-situ growth method.By characterizing ZIF/rGOAM obtained by two different reduction methods,the results show that ZIF-8 can be uniformly and tightly loaded on graphene aerogel microspheres.Compared with the microwave reduction,the thermally reduced graphene aerogel microspheres have a lower reduction degree and more oxygen-containing groups.So the thermally reduced graphene aerogel microspheres can fix a higher content of metal ions and a higher capacity of ZIF-8.As a result,it can get better performance.The obtained ZIF/rGOAM can improve the utilization filed of ZIF-8 due to the porosity of the aerogel microspheres,and has the great application potential in gas adsorption and electrode materials.