About MOF synthesis, characterization and properties, accompanied by results

1. Synthesis and characterization of Transition Met
al based Metal-Organic Framework (MOF) for
sensor applications
Abhishek Katoch
Roll no. : 14
Dr. Sanjeev Gautam
Assistant Professor in Physics
Panjab University, Chandigarh
Dr. S S Bhatnagar University Institute of
Chemical Engineering & Technology
PANJAB UNIVERSITY, CHANDIGARH -160 014
Supervisor

2.  Brief Introduction
 Critical literature review
 Expected Objectives
 Achieved Objectives
 Experiments Conducted
 Experimental Data
 Results and Discussions
 Scope for the future work
Outline of presentation

3. Introduction to MOF
What are Metal-Organic Frameworks (MOFs)?
 Rigid, crystalline, porous and non interpenetrating Structure with organic
ligands to metal centers.
 Many dicarboxylic acids (i.e. oxalic acid, malonic acid, succinic acid,
glutaric acid, terepthalic acid), tricarboxylix acid (i.e. citric acid, trimesic
acid) or azoles (i.e. 1,2,3-triazole, pyrrodiazole) are used as a linker.
 Due to vast availability of metal-ligands combinations MOFs has been
studied as the wide area of research.
Nature volume423, pages705–714 (12 June 2003)

4. Introduction to MOF
Basic properties of Metal-organic frameworks
Crystalline, Highly ordered solids
Ultrahigh surface area ( as high as 6000m2/g)
Nano porous (5-30Å)
Huge variety of structures, Structurally flexible.
Applications
 Gas storage
 Gas separation, Gas adsorption, Gas purification.
 Catalysis
 Hydrogen storage, Methane storage, Carbon dioxide storage.

5. Sr.
no Author/Journal Year Work done
1.
Synthesis, Characterization and Adsorption
Capability of MOF-5
N. Iswarya et. Al. , Asian J. Sci. Res., 5: 247-254.
2012
• samples were found to be
stable at 350°C.
• hence can be used in high
temperature applications.
• It was capable of adsorbing
gases
• hence can be used for
CO2 and H2 storage.
2. Enhanced Hydrostability in Ni-Doped
MOF-5.
Huanhuan Li et. Al. Inorg. Chem. 2012, 51,
9200−9207
2012 • Ni-doped MOF-5s
synthesized solvothermal
crystallization to enhance the
hydrostability.
• H2 uptake capacity of
undoped MOF-5 drops
rapidly when exposed to the
ambient air,
• whereas the H2 adsorptions
of the Ni-doped MOF-5s
remain stable for 4 days.
Critical literature review

6. Sr.
no
Author/journal Year Work done
3.
Study on preparation and
characterization of MOF
based lanthanide doped
luminescent coordination
polymers.
Nguyen Thanh et. Al. Materials
Chemistry and Physics
Volume 143, Issue 3, 14 February
2014, Pages 946-951
2014
• Synthesis of luminescent materials by
solvothermal method.
• MOF-5/RE with ordered structure
gives strong luminescence spectra.
• these complexes displayed intense
emissions at room temperature and
proved to be good candidates for red
and green emitter luminescent
materials.
3.
Shape and size control and
gas adsorption of Ni(II)-
doped MOF-5
nano/microcrystals.
Ji-MinYang et. Al. Microporous and
Mesoporous Materials
Volume 190, 15 May 2014, Pages 26-
31
2014
• Ni(II)-doped MOF-5 shows
enhanced moisture stability.
• The gas sorption measurements
reveal that highly crystalline
particles have large Langmuir
surface area and
• total pore volume and also
enhanced the structural stability of
MOFs towards moisture.

7. Expected Objectives
 Reduction of Energy penalty.
• Cooling of mixture
• Residence time.
 Enhancement of Hydrostability of MOF.
• Stability of MOF to a moisture
 Reduction of energy band gap.
 Doping with a element which can be helpful in sensor
application.
 To maintain a porous network and Sensing of gas.
• For adsorption of gaseous.

8. Achieved Objectives
 Reduced “Energy Penalty”. (HOW…?)
With the term “energy penalty” usually refers to the loss of energy which
often arises in the MOF during the time of cooling of mixture. Residence
time of the mixture during the time of cooling of mixture was increased in
the oven for 2 days .
 Maintained the hydrostability of the MOF.
Carried out doping of Nickel in two concentrations (1:1) &(1:9) and
analysed the XRD peaks with the data which was taken after keeping the
sample for 5days in 37% humidity. MOF was stable to the moisture.

9. Continue……..
 Reduced the energy band gap.
Energy band gap was reduced from 3.9 to 3.6 which is a good indication for
the material to behave as a sensing material.
 Doping at various concentration was successfully carried out.
 Maintained the porosity.
 Harmful gas was successfully sensed and results were
analysed.

10. Experiments Conducted
 Designed the hydrothermal autoclave .
 Sample was synthesized at various temperature profiles
 First it was synthesized for 24 hours then 36 hours finally synthesized at
1600c for 48 hours.
 Doped nickel in the modified MOF at various concentrations
(1:9) & (1:1).

11. Continue……..
 Divided prepared MOF sample of various concentration
individually in three crucibles and kept in moisture(humid air).
 Set up the sensing apparatus in the lab for the sensing of harmful
gaseous through the MOF.

12. Flow Chart (Synthesis)

13. Why solvothermal approach?
Pressure calculations:
Density=0.948 g mL−1
1 bar = 0.1mpa
Heating point of DMF= 152-1540c
We took; 1600c=376bar or 3.76MPa
prr.hec.gov.pk/Chapters/1332S-6.pdf
P[bar]
Pressure calculations:
Closed Autoclave: Autogeneous Pressure
Critical temperature: 374.150c
Critical pressure:220 bar(22.064mpa); Critical density: 0.321g/cm3
Above the critical temperature and critical pressure ;supercritical or fluid phase.
Solvothermal, General aspects
 Ion product increases
 Viscosity decreases
 Polarity (dielectric constant)
decreases, but increases with
pressure.

14. Experimental Data.
Structural characterization
 X-Ray Diffraction peaks of prepared MOF.
 X-ray diffraction peaks of MOF after keeping it in a humid atmosphere.
 Field emission Scanning electron microscopy (FE-SEM); for
morphological study.
Optical measurements:
 UV-VIS-DRS spectrometer; to obtain energy band gaps.
 Fourier transform infrared spectroscopy (FTIR).
 Photoluminescence measurement (Fluorescence Spectrophotometer).

15. X-RAY diffraction peaks
Figure shows the diffraction
Patterns of various synthesized
MOFs. Modified MOF-5 gave the
diffraction peak of about
2theta=5.470; 9.770; 10.740 and
16.11, were in good agreement
with X-ray diffraction patterns of
the synthesized doped MOF. The
Ni-doping does not changed the
diffraction peaks of MOF-5.
Reason might be low content of
Nickel doped. Inset showing that
there is not much which peak
widening in the MOF indicating to
the fact that crystallite size
remained same (25-38nm ).
D. J. Tranchemontagne et.al., Room temperature synthesof metal-
organic frameworks: Mof-5, mof-74, mof-177, mof-199, and irmof-0,
Tetrahedron 64 (36) (2008) 8553–8557.
H. Li,W. Shi, K. Zhao, H. Li, Y. Bing, P. Cheng, Enhanced
hydrostability in ni-doped mof-5, Inorganic chemistry 51 (17) (2012)
9200–9207.

16. STRUCTURAL ANALYSIS (moisture effect)
It can be clearly seen from
the patterns (moisture
hasn't effected much)
crystallinity isn't effected
much has remained same
after 5 days of exposure in
air; thus can be clearly said
that Ni-doping clearly
enhanced the
hydrostability of MOF-5

17. Fourier transform infrared spectroscopy (FTIR)
Functional
group stretch
Frequency/
wavenumbe
r
(in cm-1)
Observe
d Value
(cm-1)
Alkane C-H
bending
1350-1480 1382
Aromatic C-H
bend
675-870 745,822
C-H group in
plane bending
1225-950 1016
Zn-O stretching Around 500 544
Aromatic C-C 1500-1600 Around
1564
Zn-O
AlkaneC-H
AromaticC-H
AromaticC-C
L.-M. Yang, M. Dornfeld, P.-M. Hui, T. Frauenheim, E. Ganz, Ten
new predicted covalent organic frameworks with strong optical
response in the visible and near infrared, The Journal of Chemical
Physics 142 (24) (2015) 244706.

18. Continue……..
 Modified MOF-5, Ni doped MOF-5 (1:9), Ni doped MOF-5(1:1)
is clearly indicating the characteristic peaks of the linker used in
the sample, usually we can refer to fact that stretching and bending
for O-H disappeared in the IR spectrum of our sample,
 alternatively we are able to see the characteristic peak of
antisymmetric COO- and symmetric COO- at around 1500
cm-1 and 1386 cm-1 which refers to the bonding of Nickel to the
carboxylic group in the complex.
R. S. Kumar, S. Dananjaya, M. De Zoysa, M. Yang, Enhanced antifungal activity of ni-doped zno nanostructures under dark
conditions, RSC Advances 6 (110) (2016) 108468–108476.

19. UV-DRS (Tauc-Plot)
Band gap was calculated
using tauc-plot. Applying
the linear fit the band gap of
sample came around.
Sample Absorption
edge
Indirect
Band gap
(Tauc-Plot)
MOF-5 332 3.94
Ni doped
MOF-5
(1:9)
362 3.69
Ni doped
MOF-5
(1:1)
368 3.64
S. Bordiga, C. Lamberti, G. Ricchiardi, L. Regli, F. Bonino, A. Damin, K.-P. Lillerud, M. Bjorgen, A. Zecchina, Electronic and
vibrational propertiesof a mof-5 metal–organic framework: Zno quantum dot behaviour, Chemical communications (20) (2004)
2300–2301

20. Conductivity Measurement
Conductivity Measurements:
- Solvent: isopropyl alcohol.
- M1=0.49
- M2 =0.65
- M3=0.75

21. Photoluminescence measurement

22. Cont……
 During excitation at 220 nm, an emission spectra was recorded with the
λmax346 nm. Which for a greater extent similar to other synthesized MOFs.
Results clearly indicates that wavelength for MOF-5 coincides with DRUV-
VIS spectrum.
 MOF-5 and Ni-doped MOFs at various concentration shows emission band at
around λmax =346 nm. Photoluminescence studies are necessary to understand
the charge-transfer pathways and the different studies pointed out three type
of luminescent behavior: i) intra-ligand luminescence, ii) charge transfer
transitions; commonly called ligand to metal charge transfer (LMCT),
electron jump from ligand orbital to predominantly metal orbital and iii)
metal-to-ligand charge transfer (MLCT). Ligand luminescence has been
investigated by employing large number of 3d elements. Most commonly
reported MOF structures are based on Zn2+ which have filled d orbitals and
thus d-d transitions are forbidden
D.-B. Records, definition-d-block, Group 3 (4) 5.
V. E. Kaasjager, L. Puglisi, E. Bouwman,W. L. Driessen, J. Reedijk, Synthesis, characterization and crystal structures of nickel complexes with
dissymmetric tetradentate ligands containing a mixed-donor sphere, Inorganica Chimica Acta 310 (2) (2000) 183–190.
G. B. Kauman, Inorganic chemistry, (miessler, gary l.; tarr, donald a.) (2000).

23. BET Analysis
---MOF-5
-----Ni-doped MOF (1:1)
Brunauer–Emmett–Teller
Surface area: 51.416m2/g
Single point BET: 52.5205m2/g
Langmuir surface area: 76.016m2/g
Avg pore radius: 1.55216e+01Å
Surface area: 51.416m2/g
Single point BET: 52.5205m2/g
Langmuir surface area: 76.016m2/g
Avg pore radius: 1.55216e+01Å

24. Element [weight.%] [atomic.%]
Oxygen 19.62 22.90
Zinc 37.72 10.77
Carbon 42.66 66.33
(a) (b)
(c)
samples have unveiled the formation o
a clump with nebulous grains

25. Element [weight.%] [atomic.%]
Oxygen 34.95 35.14
Zinc 17.65 4.34
Carbon 44.88 60.09
Nickel 1.18 0.32
Gold 1.33 0.11
(a) (b)
(c)

26. Element [weight.%] [atomic.%]
Oxygen 25.54 23.14
Zinc 9.03 2.00
Carbon 61.14 73.80
Nickel 4.29 1.06
(a) (b)
(c)

27. Analysis
Large number of tiny pores can be seen which are inside the
cluster of particles clearly indicating porous nature of the
complex. Therefore the technique of fragmented doping while
preparing the complex using higher concentration dopant can
concur to the fact that higher doping gives large-scale particles
What is NO2 gas?
It is one of several nitrogen oxides. NO2. is an intermediate in the industrial
synthesis of nitric acid, millions of tons of which are produced each year. At
higher temperatures it is a reddish-brown gas that has a characteristic sharp,
biting odor and is a prominent air pollutant.

28. Sensor application
M1,M2,M3= Samples
Reaction involved in gas Production
If HNO3 concentrated and is in excess then the ratio is 1:4
copper to nitric acid. If it is dilute then the ratio is 3:8.

29. Response to Gas
UV-DRS spectroscopy of
the Sample were done
which were exposed to the
harmful gas. Band gap was
reduced to around 3.56eV.
And for the MOF-5 we
cant see any peak;
indicating complex has
responded to uv and is
behaving like a metal.

30. CONCLUSIONS
 Porous MOF-5 and Ni-doped MOF at various concentrations was
successfully synthesized by solvothermal reaction.
 Fragmented doping of Ni(II) ions in the MOF-5 complex has been
successfully carried out
 FTIR analysis confirmed the presence of stretching bands in the
prepared MOFs
 Sensing of the Gas was successfully carried out.
 Prepared samples were responsive to gas.

31. SCOPE for future work
Cheap
Sensitivity
Selectivity
Low maintenance cost
Fast in response
Harmful Gases

32. Thank you for your kind attention
Acknowledgements
1.TEQIP-III grants are acknowledged.
2. Co-researcher and Support staff (Mr. Sethi) in applied Physics
laboratory are duly acknowledged.