Oriented Crystallisation on Supports and Anisotropic Mass Transport of the Metal‐Organic Framework Manganese Formate

Abstract

The oriented in situ crystallisation of microporous manganese(II) formate [Mn(HCO 2 ) 2 ] on different porous supports (e.g. porous alumina and graphite) has been investigated. The anisotropic growth of Mn(HCO 2 ) 2 was examined by Xray diffraction (XRD) and scanning electron microscopy (SEM). The intracrystalline diffusion of methanol in Mn(HCO 2 ) 2 was studied by observation of the sorption kinetics by interference microscopy (IFM). It was found that untreated discs of porous alumina and graphite supports exhibit poor densities of Mn(HCO 2 ) 2 crystals per supported area. Even lower crystal densities are found for activated supports such as for alumina after basic treatment and for oxidized graphite supports. Improved results have been achieved by replacing formic acid by sodium formate in the synthesis

Novel MOF‐Membrane for Molecular Sieving Predicted by IR‐Diffusion Studies and Molecular Modeling

“…Often pinholes and cracks of membranes as well as poorly performing microporous materials show this type of selectivity. Even though there have been increasing attempts to develop MOF-based molecular sieve membranes, [5][6][7][8][9][10] only in recent publications membranes are reported, which perform better than the Knudsen separation. [11][12][13][14][15] In view of the cost of development and the uncertainty of the performance of new MOFs, a computerbased screening and pre-selection method is desired.…”

Metal–organic framework growth at functional interfaces: thin films and composites for diverse applications

“…For example, Arnold et al prepared membranes of Mn(HCO 2 ) 2 , which contains a 1-D pore structure, on both graphite and alumina supports. 62 Diffraction analysis of 60 the composites revealed the 1-D channel system of the framework was parallel rather than perpendicular to the alumina although the pore system could become better oriented dependent on synthetic conditions. Oriented microporous MOF membranes can be prepared from 65 randomly oriented seed layers.…”

“…One of the most successful methods to prepare such films utilises 30 a 'seeding and secondary growth' approach, which is employed to favour MOF nucleation on the substrate rather than in solution and has now been applied to a number of MOF types. It is noted that the properties of the seed layers in terms of adherence to the support, seed particle size, anisotropy and orientation, as well as 35 how the support itself has been prepared 62 , are all important factors for the successful preparation of supported MOF membranes.…”

Liquid-phase epitaxy of metal organic framework thin films

“…Even for a bare substrate (without any functional groups, like silica), crystal sizes increase as deposition process proceeds [29]. However, no crystal is generated when the filtrated mother solution is kept where it is.…”