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Transcript of OWENGLEDHILL_FULL REPORT_FINAL
POWDER X-RAY DIFFRACTION STUDY OF ZEOLITIC IMIDAZOLATE FRAMEWORK-8
Owen J. Gledhill
ID22, European Synchrotron Radiation Facility ESRF,
Powder X-ray diffraction was used at ID22 at the ESRF to study the zeolitic imidazolate
framework ZIF-8. ZIF-8 was synthesised using a variety of methods, all of which were
adapted from previously reported studies. The diffraction patterns of the samples from the
different syntheses were analysed using Pawley and Rietveld refinement techniques.
Samples produced in DMF, ethanol and acetone produced ZIF-8 in good agreement with
the literature. It was decided that the samples produced in DMF were most suitable for gas
adsorption measurements. The effects of loading CO2 onto the samples up to pressures of
12.5 bar were studied. The gas adsorption measurements showed an expansion of the unit
cell as CO2 pressure was increased. It was seen that CO2 occupied the pores of the
framework but with no specific interactions between the framework and the gas molecules.
Theoretical calculations on the gas position, average gas loading and pore structure were
performed for comparison with the empirical findings. In general, there was good
agreement between the two but it would be useful to perform further measurements with
different gases as well as industrially relevant gas mixtures. There was an issue with
solvent remaining in the pores once synthesised, even after evacuation of the samples.
Further studies would include solvent exchanges in an effort to completely remove it and
thus make gas adsorption measurements more accurate.
Zeolitic Imidazolate Frameworks (ZIFs) such as ZIF-8 are a class of compounds which
have recently garnered much interest due to the properties that they possess. Specifically,
they tend to be highly crystalline, highly porous and ZIF-8 in particular is extremely
thermally and chemically stable . These properties make ZIFs particularly attractive as
candidates for applications such as gas storage, gas separation and catalysis.
This project aimed to investigate the synthesis of ZIF-8 using a range of synthetic
techniques based on those reported in previous studies, followed by analysis of the samples
to choose the most appropriate candidate for gas adsorption measurements. Also to
examine the effect of adsorbing CO2 gas onto the ZIF-8 samples and gain an insight into
the behaviour of the gas once inside the pores.
The European Synchrotron Radiation Facilitys high resolution powder X-ray
diffraction (PXRD) beamline, ID22, was used to collect diffraction patterns. Patterns were
collected on all the as synthesised samples as well as selected samples which had CO2 gas
loaded onto them over a range of pressures. The diffraction patterns were indexed and
refined to gain structural information as well as being the basis for calculating the position
of gas molecules within the pores. Several pieces of specialised software were used to
perform these calculations such as TOPAS which was used for refinements; Materials
Studio which was used for 3D modelling of the structures and gas position determination;
and Mercury which was used to model the pore structures.
It was seen that ZIF-8 was successfully synthesised using several of the methods
tried and that they were in accordance with the literature data. However, for the samples
produced in DMF, there was an issue with solvent remaining in the pore and a ZnO
impurity being present. The gas adsorption experiments showed that CO2 was readily
adsorbed into the pores of ZIF-8 which was indicated by an increasing lattice parameter as
the gas pressure was increased. It was shown that there were no specific interactions
between the framework and the CO2 molecules which was probably due to the fact that all
the metal binding sites are occupied in ZIF-8. The theoretical calculations showed good
agreement with the empirical results.
There are some limitations with the results of the study. For example, the fact that
there was an impurity in some of the samples and solvent remained in some of the pores,
could reduce the accuracy of the gas adsorption results. This is because the pores would
already be partially filled, and hence prevent the maximum amount of CO2 being adsorbed.
Also, another issue faced was that ZIF-8 appeared to be very sensitive to radiation and only
very short scans could be taken. This suggests that PXRD isnt a perfect technique for the
analysis of ZIF-8 and it would perhaps benefit from being coupled with other techniques
such as elemental analysis and spectroscopy.
The European Synchrotron Radiation Facility (ESRF) is Europes most powerful
synchrotron located in Grenoble, France and is an internationally renowned research
institute. More than 6000 users and around 600 staff perform experiments in an
increasingly wide range of scientific areas every year at one of the ESRFs 41 highly
specialised beamlines. From the 1500 experiments performed yearly at the ESRF, over
2000 publications are produced which equates to over 20,000 since its inception in 1994
The ESRF operates with a budget of around 80M a year which is provided by the ESRF
member states as well as some additional contributors .
ESRF Member contributions:
27.5% France 24% Germany 13.2% Italy 10.5% United Kingdom 6% Russia 4% Spain 4% Switzerland 5.8% Benesync (Belgium, The Netherlands) 5% Nordsync (Denmark, Finland, Norway, Sweden)
1.5% Israel 1.3% Austria 1% Poland 1% Portugal 1.05% Centralsync (Czech Republic, Hungary, Slovakia) 0.3% South Africa
ESRF history: 
1975: Idea for a European third-generation synchrotron source
1988: Signing of the agreement between the governments of 12 Member States
1992: First electron beam in the storage ring. Commissioning phase.
1994: User operation begins with 15 beamlines
1998: Forty beamlines in operation
2009: Start of the ESRF Upgrade Programme
2011: Inauguration of the first Upgrade Beamline
2015: Completion of Phase I Upgrade Programme
The ESRF and similar facilities
The ESRF is Europes premier synchrotron facility, which operates at 6 GeV. However,
there are many other synchrotron facilities in Europe, such as Diamond in the UK (3 GeV)
and ALBA in Spain (3 GeV); as well higher energy synchrotrons outside Europe like
SPring-8 in Japan (8 GeV) and the APS in the USA (7 GeV) .
The ESRF differs from these other facilities as it employs staff from more than 40
countries who are typically on short term contracts which promotes innovation and ensures
that new ideas are always being brought to the ESRF .
Beamlines and science at the ESRF
Figure 1 shows the layout of the ESRF with the beamlines running tangential to the storage
ring as well as where the different types of beamlines are positioned.
Figure 1. Layout of ESRF beamlines after completion of Phase I upgrade .
There are two types of beamline based on the way in which X-rays are produced.
These being insertion device (ID) or bending magnet (BM) beamlines. Most BM
beamlines are CRG (collaborating research groups) beamlines and are not operated by the
ESRF but by external institutions from ESRF member states .
The diverse range of techniques used at the beamlines is what allows such a wide
range of science to be carried out at the ESRF. The ESRF currently performs research in
areas from chemistry to paleontology, and physics to biochemistry as shown in figure 2.
Figure 2. Scientific research areas studied at the ESRF 
Users at the ESRF help to drive this diversification of science carried out at the ESRF.
Users from external institutes submit proposals for time at one of the beamlines to perform
their experiments. Proposals are considered twice a year and are reviewed by independent
review committees . They are chosen using criteria such as scientific merit, and
beamtime is also allocated according to the percentage stake each member state has in the
ESRF. Beamtime is free for users of member countries if their research is made public .
However, the number of industrial users is increasing at the ESRF as they have access to
techniques that are not available at any other facilities. Figure 3 shows some of the
industrial sectors that use the ESRF.
Figure 3. Industrial sectors using the ESRF 
My Role at the ESRF
I am part of the experiments division which is one of six divisions at the ESRF which
covers all aspects of the organisation. The experiments division is further divided into
beamline groups which have similar research areas. I work on beamline ID22 which is one
of five in the structure of materials group as shown in figure 4.
Figure 4. Organisation of structure of materials group 
ID01: Microdiffraction imaging
ID03: Surface diffraction
ID11: Materials science, time resolved diffraction
ID15A/B: High energy diffraction/scattering
ID22: Powder diffraction Me
ID22 is the ESRFs high res