cm7b03096_si_001.pdf (1.6 MB)
In Situ Time-Resolved Attenuated Total Reflectance Infrared Spectroscopy for Probing Metal–Organic Framework Thin Film Growth
journal contribution
posted on 2017-09-21, 00:00 authored by Junjie Zhao, Berc Kalanyan, Heather F. Barton, Brent A. Sperling, Gregory N. ParsonsIn 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 studying
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.