Crystals Growth Study of Microporous Metal-Organic Frameworks by Atomic Force Microscopy

  • Samaila Jovial

Student thesis: Master of Science by Research

Abstract

Porous materials are one of the extensively used class of solid mostly useful for adsorption, catalysis, separation, storage and ion exchange. Microporous materials have received a rapidly growing rate of interest with regards to their syntheses, characterisation and applications. In the current study ex-situ atomic force microscopy (AFM) was used to investigate the crystal surfaces of MOF-801-SC and Zn(tbip) crystals to provide information concerning the crystal growth of the materials.MOF-801-SC is a novel porous coordination polymer (PCP) and a member of the Zr-based UiO-66 series as seen by powder X-ray diffraction (PXRD), composed of zirconium (iv) oxychloride octahydrate (ZrOCl2.8H2O), and fumarate (-O2C(CH)2CO2-) linkers has been synthesised by a modulated synthesis approach. MOF-801-SC further characterised by scanning electron microscopy (SEM) revealing that the crystals have octahedral cubic morphology with crystal sizes ranging from 7.0 µm to 9.0 µm. The AFM height images analyses revealed that most of the growth steps are 1.0 ± 0.1 nm high.Zn(tbip) is a novel guest-free Microporous metal-organic framework (GFMMOF) composed of Zn-based secondary building units (SBUs), [Zn(NO3).6H2O], and 5-tert-butyl isophthalate (tbip2-) ligands has been synthesised and characterised structurally robust with an extraordinary thermal stability. The PXRD pattern of the sample indicated that a monophasic sample had been prepared. The SEM revealed that the crystals have elongated hexagonal prism morphology with crystals sizes ranging from 300 µm to 500 µm. Thermogravimetric analysis (TGA) showed that the crystal is thermally stable up to 420 oC and is guest molecule free. Single crystals were determined by single crystal X-ray diffraction (SXRD). Solid-state NMR proved that the crystals are guest-free. SXRD showed that methanol addition to the single crystals proved that a molecule can go into the crystal pores. A multilayer growth features were observed in the AFM micrographs of Zn(tbip) crystals.
Date of Award1 Aug 2015
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorMichael Anderson (Supervisor) & Martin Attfield (Supervisor)

Keywords

  • Atomic Force Microscopy
  • Metal-Organic Framework
  • Crstal growth
  • Microporous

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