Simultaneous neutron powder diffraction and microwave dielectric studies of ammonia absorption in metal–organic framework systems

Ammonia absorption has been investigated in metal–organic frameworks (UiO-67, HKUST-1 and CPO-27-Co) using custom-built apparatus that allows simultaneous neutron powder diffraction (NPD), microwave dielectric characterisation and out-gas mass spectroscopy of solid-state materials during ammonia adsorption. Deuterated ammonia was flowed through the sample and absorption monitored using mass flow meters and mass spectroscopy. Argon gas was then flowed through the ammoniated sample to cause ammonia desorption. Changes in structure found from NPD measurements were compared to changes in dielectric characteristics to differentiate physisorbed and metal-coordinated ammonia, as well as determine decomposition of sample materials. The results of these studies allow the identification of materials with useful ammonia storage properties and provides a new metric for the measurement of gas absorption within mesoporous solids.
The datasets here are linked to all of the key graphs in the paper. These are in two main sections, namely (1) microwave data, taken from resonant cavity measurements; (2) neutron diffraction data, taken simultaneously with the microwave data.

Research results based upon these data are published at http://doi.org/10.1039/C8CP00259B