氧化石墨烯/ZIF-7复合材料的制备与性能

Preparation and performance of graphene oxide/ZIF-7 composites

  • 摘要: 本文采用3种合成路线实现了ZIF-7在氧化石墨烯(GO)上的原位生长,并通过PXRD、FTIR、SEM、TEM和N2吸附-脱附等对氧化石墨烯/ZIF-7复合材料(GO/ZIF-7,简写为GZR-n,其中n 代 表合成路线 I、II、III)进行了表征。研究了合成路线对ZIF-7晶体在GO上的原位生长、结晶度、微观形貌和孔径大小的影响。结果显示:通过3种合成路线均可实现ZIF-7晶体在GO表面及其片层间的原位生长,且其结晶度明显增强,部分ZIF-7晶体被GO包裹。ZIF-7晶体形貌和粒径大小在GZR-n上的原位生长受到合成路线的影响,其中,ZIF-7晶体在GZR-II中呈50 nm的纳米球状颗粒,在GZR-I和GZR-III中则形成200 nm的规则多面体。进一步研究了ZIF-7、GO和GZR-n在不同极性溶剂中的分散性能及其对有机染料的吸附性能和动力学行为。GZR-n在甲醇和氯仿中表现出良好的分散性。与ZIF-7晶体相比,GZR-I、GZR-II和GZR-III对亚甲基蓝的吸附能力分别提高了226%、302%和278%,动力学模拟结果显示,GZR-II和GZR-III对亚甲基蓝的吸附属于化学吸附,而GZR-I对亚甲基蓝的吸附属于物理吸附。

     

    Abstract: ZIF-7 crystals were in situ grown on graphene oxide (GO) by three synthetic routes, and the resulting graphene oxide/ZIF-7 composites (GZR-n) were characterized by PXRD, FTIR, SEM, TEM, and N2 isothermal adsorption-desorption. The effects of the synthetic routes on the growth, crystallinity, microscopic morphology and pore size of ZIF-7 crystals on GO were investigated. ZIF-7 crystals were grown on the surface and sheet of GO by three synthetic routes. The crystallinity of ZIF-7 crystals on GZR-n was significantly enhanced and some were wrapped by GO. The shape and size of ZIF-7 crystals growing on GZR-n were modulated by the synthesis routes. In particular, the ZIF-7 crystals are spherical particle with a diameter of 50 nm in GZR-II. For GZR-I and GZR-III, the ZIF-7 crystals are regular polyhedron with a size of 200 nm. Additional, their dispersion properties in solvents, adsorption properties and kinetic simulations for organic dyes were explored. GZR-n show good dispersion in methanol and chloroform. Compared with ZIF-7 crystals, the adsorption capacities of GZR-I, GZR-II and GZR-III for methylene blue are increased by 226%, 302% and 278%, respectively. The kinetic simulations indicate that the adsorption of GZR-II and GZR-III for methylene blue are chemisorption and that of GZR-I is physical adsorption.

     

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