Chemical Research in Chinese Universities ›› 2014, Vol. 30 ›› Issue (3): 356-361.doi: 10.1007/s40242-014-3349-y

Previous Articles     Next Articles

Synthetic Control Method for Crystallite Size of MOF-5

HAN Pengfei, YUAN Changfu, XU Junyi, LIU Jin   

  1. School of Metallurgy and Environment, Central South University, Changsha 410083, P. R. China
  • Received:2013-08-19 Revised:2013-10-31 Online:2014-06-01 Published:2013-11-25
  • Contact: LIU Jin E-mail:liujincsu@163.com
  • Supported by:

    Supported by the National Natural Science Foundation of China(No.51274239), the Fundamental Research Funds for the Central Universities of Central South University, China(No.2013zzts191) and the Open-end Fund for the Valuable and Precision Instruments of Central South University, China(No.CSUZC2013028).

Abstract:

We reported a dripping solvothermal method for synthesizing metal-organic framework-5(MOF-5). It started from separately dissolving Zn(NO3)2 and terephthalic acid(H2BDC) in dimethyl formamide(DMF), and then dripping one solution into the other. Results of SEM, XRD and laser particle size distribution show that regular cubic-shaped and micro-crystallite powder of MOF-5 can be obtained. The d0.5(volume-median-diameter) values are 4.32 μm for particles prepared by dripping Zn(NO3)2 into H2BDC(ZH) and 9.32 μm for those prepared by dripping H2BDC into Zn(NO3)2(HZ), much smaller than 22.7 μm that of particles prepared by the traditional adding water solvothermal method(L). The standard deviations of the particle size distributions fitted by the GaussAmp model are 2.49, 4.38 and 15.4 respectively for ZH, HZ and L, further revealing narrower size distributions of particles prepared by the dripping method. In addition, the Langmuir specific surface areas are 923 m2/g for ZH and 868 m2/g for HZ. The TGA results present mass losses of 4.18% and 3.62% at 105 ℃, 17.19% and 14.78% at 245 ℃, 39.04% and 34.85% at 600 ℃ separately for ZH and HZ, which correspond to the removal of H2O, DMF and the decomposition of MOF-5. This indicates that MOF-5 has a strong adsorption ability for small molecules. Besides, the mass loss of 48.39%(ZH) and 41.02%(HZ) between 400 ℃ and 600 ℃ are less than the theoretical value of 57.81% for MOF-5 decomposition to ZnO, suggesting that an impure phase with an extra amount of ZnO may exist in the cavities of MOF-5.

Key words: Metal-organic framework-5(MOF-5), Dripping solvothermal method, Size distribution