In Situ Time-Resolved Attenuated Total Reflectance Infrared Spectroscopy for Probing Metal–Organic Framework Thin Film Growth

Abstract

In situ chemical measurements of solution/surface reactions during metal-organic framework (MOF) thin film growth can provide valuable information about the mechanistic and kinetic aspects of key reaction steps, and allow control over crystal quality and material properties. Here, we report a new approach to study the growth of MOF thin films in a flow cell using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Real-time spectra recorded during continuous flow synthesis were used to investigate the mechanism and kinetics that govern the formation of (Zn, Cu) hydroxy double salts (HDSs) from ZnO thin films and the subsequent conversion of HDS to HKUST-1. We found that both reactions follow pseudo-first order kinetics. Real-time measurements also revealed that the limited mass transport of reactants may lead to partial conversion of ZnO to HDS and therefore leaves an interfacial ZnO layer beneath the HDS film providing strong adhesion of the HKUST-1 coating to the substrate. This in situ flow-cell ATR-FTIR method is generalizable for studying the dynamic processes of MOF thin film growth, and could be used for other solid/liquid reaction systems involving thin films.

Templated fabrication of hierarchically porous metal–organic frameworks and simulation of crystal growth

“…This is a key step to rapidly form H-MOF crystals. 41,42,65 Meanwhile, the introduced DMOA surfactant forms supramolecular micelles through self-assembly, a key step to generate mesopores and macropores. 64 Upon the addition of (Cu, Zn) HDS to the micelle solution, the Cu 2+ and BTC 3À rapidly selfassemble on the surface of the template micelles due to the high anion exchange rate.…”

Formation of block-copolymer-templated mesoporous silica

“…19,11 Tejedor-Tejedor et al 20 showed that ATR is suitable for monitoring the hydrolysis of TEOS, and it has also been used to study the formation of mesoporous films in dip coating. [21][22][23] To our knowledge, the presented study is the first to follow the formation of mesoporous particles using in situ ATR.…”

Atomic Layer Deposition-Derived Nanomaterials: Oxides, Transition Metal Dichalcogenides, and Metal–Organic Frameworks

“…The obtained HKUST-1 film shows a well-behaved crystallization according to the XRD results (Panel (ii) of Figure a), in which the HKUST-1’s patterns are in accordance with the simulated patterns. The MOF coating showed a stable adhesion because of the partially unconverted ZnO layer. , …”

“…(iii) Time-resolved infrared absorption spectra for surface reactions to form the HKUST-1 film. Adapted with permission from ref . Copyright American Chemical Society 2017.…”

“…Figure exhibits typical the applications and corresponding performances of these MOF-based structures, which are produced by the AIG-liquid strategy. Generally, MOFs were considered to have the potential for gas screening or gas separation because of its porous nature. , Thus, MOF films prepared by AIG also demonstrated remarkable achievements in this respect. − …”