CO 2 Adsorption in Heterometallic Metal- Organic Frameworks BY: ANTHONY CAMPANELLA MENTORS: BEN TRUMP & CRAIG BROWN
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CO2 Adsorption in Heterometallic Metal-Organic FrameworksMENTORS:
BEN TRUMP & CRAIG BROWN
Background Porous materials have the potential to play a large role in future energy technologies
H2 and CH4 storage and selective adsorption of CO2 from industrial exhaust
Extremely high surface areas—~1,000 m2/g for zeolites and ~10,000 m2/g for metal-organic frameworks
With porous material present
Presentation Notes
Important b/c can store more gas at milder conditions than free space H2 and CH4 are fuels—more efficient storage methods would make them a more competitive against liquid petroleum Being able to selectively adsorb CO2 from industrial exhaust would greatly reduce the amount of carbon in the atmosphere Their ability to adsorb high amounts of molecules is due to the large surface areas they have
Metal-Organic Frameworks (MOFs) Composed of organic ligands coordinated to a metal center
High surface-area to mass ratios, low densities and thermal expansion indices
Tunable—thousands of combinations of metals and ligands exist, with many more to be discovered
Heterometallic MOFs contain more than one metal
Eddaoudi, M. Science 2002, 295 (5554), 469–472.
Presenter
Presentation Notes
Metal is usually a transition metal Densities less than or about 1 g/cc Second image is a more detailed diagram of a MOF unit cell, highlighting the large pore volume Describe Video
Motivation A recent paper published in JACS asserted that certain heterometallic MOFs had: Exceptionally high CO2 uptakes, isosteric heats of adsorption (Qst) and surface areas Qst numbers for V/Mg are record breaking
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
1459 m2/g (Fe/Mg)
1347 m2/g (In/Mg)
1011 m2/g (V/Mg)
Presentation Notes
This is really great b/c we have MOFs that really energetically adsorb CO2 Though this is not necessarily optimal b/c hard to remove Typical Qst is between 20-30 So we want to confirm these results Describe exactly what Qst is (Physically)
The MOFs Investigated Synthesized in collaboration with Prof. Eric Bloch’s lab at the University of Delaware
Activated and prepared for characterization at the NCNR
N N
Presenter
Presentation Notes
MOFs synthesized prior to the summer Here we have the ligand, two isophthalic acid molecules bridged by an azo group The other image shows how the ligand binds to the three metals with octahedral geometry around each metal center
Synthesis and Activation
Fe/Mg MOF V/Mg MOFIn/Mg MOF 100 200 300 400 500 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
100
Water + DMA
Presentation Notes
MOFs were synthesized by me M = Metal (Fe or V) Activation conditions were determined by thermogravimetric analysis MOFs were obtained by filtration then activated at 80-120C in vacuum to remove residual solvent Activation important for having room to adsorb gas Stored in glove box to prevent contamination with water, CO2, and oxygen Crystallinity was confirmed by powder X-Ray diffraction done at UMD
Gas Adsorption Conducted on a system built in house
Surface area, pore volumes, and Qst can be determined from adsorption data
Brunauer-Emmett-Teller (BET) theory describes multilayer adsorption
CO2 isotherms at two temperatures can be used to determine Qst through the Virial Equation
ln = ln + 1 ∑ + ∑
= −2 ln
= −∑
Presentation Notes
Now that we have crystalline materials, we have to see if we can reproduce their data To do so we run gas adsorption isotherms using this Sievert system built by Dr. Taner Yildirim Explain system diagram BET theory explains multilayer adsorption of gas to a solid surface (assuming gas goes to liquid phase) The Virial eq is a model that can fit isotherm data for a non-ideal gas
N2 Adsorption Isotherms for Fe/Mg MOF
0 100 200 300 400 500 600 700 800 0
50
100
150
200
250
300
350
400
450
500
550
BET Surface Area: 1246 m2/g Pore Volume: 0.55 cc/g
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
Published Isotherm Experimental Isotherm
BET Surface Area: 1459 m2/g Pore Volume: 0.72 cc/gBET Surface Area: 1459 m2/g
Pore Volume: 0.72 cc/g
Presentation Notes
On the left we have the published uptake of N2 at 77K On the right we have our uptake from the same adsorption experiment we ran
N2 Adsorption Isotherms for V/Mg MOF
BET Surface Area: 1019 m2/g Pore Volume: 0.429 cc/g
BET Surface Area: 1011 m2/g Pore Volume: 0.50 cc/g
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
0 100 200 300 400 500 600 700 800 0
50
100
150
200
250
300
350
400
Presentation Notes
On the left we have the published uptake of N2 at 77K On the right we have our uptake from the same adsorption experiment we ran
Comparison to the Full Data
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
77 K
0 100 200 300 400 500 600 700 800 900 0
100
200
300
400
500
Presentation Notes
Our data lines up with where most of the MOFs have their uptakes lining up
CO2 Adsorption Isotherms for Fe/Mg
0 100 200 300 400 500 600 700 800 900 1000 0
20
40
60
80
100
120
140
160
180
200
220
Fe/Mg MOF CO2 Adsorption
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
Published Isotherm Experimental Isotherm
Presentation Notes
Our data produces a much lower CO2 uptake than the published data, even when going out to higher pressures
CO2 Adsorption Isotherms for V/Mg
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
0 100 200 300 400 500 600 700 800 900 1000 0
20
40
60
80
100
120
140
160
180
Presentation Notes
Our data produces a much lower CO2 uptake than the published data, even when going out to higher pressures
Heats of Adsorption V/Mg
Fe/Mg
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 0
10
20
30
40
50
60
70
80
90
100
Presentation Notes
Using our data and the virial equation we got this plot Fe/Mg is very close, but V/Mg was very different Lines up with the bulk of measurements published Remind Qst meaning
Diffraction Waves of angstrom scale diffract off of a crystal lattice and produce a distinct pattern
This diffraction is described in Bragg’s Law: 2 sin =
X-rays and thermal neutrons have the correct wavelength ranges X-rays: 1 Å - 2 Å Neutrons: 1.2 Å - 2.08 Å
Presenter
Presentation Notes
Since we see these discrepancies with the adsorptions, the next step is to check the structure Neutron Diffraction is the primary method I used for structural characterization this summer
Neutron Diffraction Why neutrons? With X-Ray diffraction there is difficulty seeing lighter elements when contrasted by metals Neutrons can detect these lighter elements in conjunction with the metals
High-Resolution Powder Diffractometer (BT-1) was used to confirm structure of synthesized MOFs
MOFs were dosed with stoichiometric amounts of CO2 during diffraction experiment
Presenter
Presentation Notes
NCNR is only place that does molar dosing in conjunction with neutron diffraction
Powder sample in vanadium canBT-1
Presenter
Presentation Notes
Photo of BT-1, Sample is placed in the middle Sample can is filled with powder and sealed. Attached to CCR system where temperature is controlled
CCR attached to CO2 line for gas dosingSample in aluminum can—ready for the beam
Presenter
Presentation Notes
Sample is encased in aluminum to seal it Chamber is put under vacuum—cooled with liquid helium ~7K A set volume is filled to a specific pressure then opened to the system to be adsorbed by the MOF
Diffraction Patterns of Fe/Mg MOF
0 5 10 15 20 25 30 35 40 0
500
1000
1500
2000
2500
3000
3500
4000
In te
ns ity
(C ou
nt s)
2θ (o)
2 Eq Dose 1 Eq Dose 2/3 Eq Dose 1/3 Eq Dose No CO2
Presenter
Presentation Notes
These are the patterns produced by BT-1 for the Fe/Mg MOF Key difference spotted with the first peak that gets bigger at 1 eq dose and 2 eq dose
Diffraction Patterns of In/Mg MOF
0 5 10 15 20 25 30 35 40 0
1000
2000
3000
4000
5000
6000
7000
In te
ns ity
(C ou
nt s)
2θ (o)
1 Eq Dose 2/3 Eq Dose 1/3 Eq Dose No CO2
Presenter
Presentation Notes
These are the patterns for the In/Mg MOF Disappearance of some small peaks
Bare Structure Fit of Fe/Mg MOF
0 10 20 30 40 50 60 70 80 90 100 0
2000
4000
6000
8000
10000
12000
14000
16000
0 20 40 60 80 100 120 140 0
2000
4000
6000
8000
10000
12000
14000
16000
Presentation Notes
From this we get the structure with CO2 and Water Multiple Orientations of water Generally describe more 1/3 Dose
CO2
H2O
Presenter
Presentation Notes
Structure w/ CO2 and water CO2 displaces water Hydrogen bonding interactions
Conclusions and Future Work Data derived from adsorption isotherms fall in the expected range for open metal site MOFs
Structure is correct—Right materials are produced
CO2 binds to open metal site, displacing water molecule
Further studies into the effects of water on adsorption
Inductively Coupled Plasma-Optical Emission Spectroscopy to determine metallic ratios
More structural and isotherm data
Acknowledgements Mentors: Ben Trump & Craig Brown
Prof. Eric Bloch, Eric Gosselin
Dr. Taner Yildirim
Center for High Resolution Neutron Scattering
All the NCNR SURFers
Background
Comparison to the Full Data
CO2 Adsorption Isotherms for Fe/Mg
CO2 Adsorption Isotherms for V/Mg
Heats of Adsorption
Bare Structure Fit of Fe/Mg MOF
Preliminary Refined Structure with CO2
Slide Number 22
Background Porous materials have the potential to play a large role in future energy technologies
H2 and CH4 storage and selective adsorption of CO2 from industrial exhaust
Extremely high surface areas—~1,000 m2/g for zeolites and ~10,000 m2/g for metal-organic frameworks
With porous material present
Presentation Notes
Important b/c can store more gas at milder conditions than free space H2 and CH4 are fuels—more efficient storage methods would make them a more competitive against liquid petroleum Being able to selectively adsorb CO2 from industrial exhaust would greatly reduce the amount of carbon in the atmosphere Their ability to adsorb high amounts of molecules is due to the large surface areas they have
Metal-Organic Frameworks (MOFs) Composed of organic ligands coordinated to a metal center
High surface-area to mass ratios, low densities and thermal expansion indices
Tunable—thousands of combinations of metals and ligands exist, with many more to be discovered
Heterometallic MOFs contain more than one metal
Eddaoudi, M. Science 2002, 295 (5554), 469–472.
Presenter
Presentation Notes
Metal is usually a transition metal Densities less than or about 1 g/cc Second image is a more detailed diagram of a MOF unit cell, highlighting the large pore volume Describe Video
Motivation A recent paper published in JACS asserted that certain heterometallic MOFs had: Exceptionally high CO2 uptakes, isosteric heats of adsorption (Qst) and surface areas Qst numbers for V/Mg are record breaking
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
1459 m2/g (Fe/Mg)
1347 m2/g (In/Mg)
1011 m2/g (V/Mg)
Presentation Notes
This is really great b/c we have MOFs that really energetically adsorb CO2 Though this is not necessarily optimal b/c hard to remove Typical Qst is between 20-30 So we want to confirm these results Describe exactly what Qst is (Physically)
The MOFs Investigated Synthesized in collaboration with Prof. Eric Bloch’s lab at the University of Delaware
Activated and prepared for characterization at the NCNR
N N
Presenter
Presentation Notes
MOFs synthesized prior to the summer Here we have the ligand, two isophthalic acid molecules bridged by an azo group The other image shows how the ligand binds to the three metals with octahedral geometry around each metal center
Synthesis and Activation
Fe/Mg MOF V/Mg MOFIn/Mg MOF 100 200 300 400 500 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
100
Water + DMA
Presentation Notes
MOFs were synthesized by me M = Metal (Fe or V) Activation conditions were determined by thermogravimetric analysis MOFs were obtained by filtration then activated at 80-120C in vacuum to remove residual solvent Activation important for having room to adsorb gas Stored in glove box to prevent contamination with water, CO2, and oxygen Crystallinity was confirmed by powder X-Ray diffraction done at UMD
Gas Adsorption Conducted on a system built in house
Surface area, pore volumes, and Qst can be determined from adsorption data
Brunauer-Emmett-Teller (BET) theory describes multilayer adsorption
CO2 isotherms at two temperatures can be used to determine Qst through the Virial Equation
ln = ln + 1 ∑ + ∑
= −2 ln
= −∑
Presentation Notes
Now that we have crystalline materials, we have to see if we can reproduce their data To do so we run gas adsorption isotherms using this Sievert system built by Dr. Taner Yildirim Explain system diagram BET theory explains multilayer adsorption of gas to a solid surface (assuming gas goes to liquid phase) The Virial eq is a model that can fit isotherm data for a non-ideal gas
N2 Adsorption Isotherms for Fe/Mg MOF
0 100 200 300 400 500 600 700 800 0
50
100
150
200
250
300
350
400
450
500
550
BET Surface Area: 1246 m2/g Pore Volume: 0.55 cc/g
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
Published Isotherm Experimental Isotherm
BET Surface Area: 1459 m2/g Pore Volume: 0.72 cc/gBET Surface Area: 1459 m2/g
Pore Volume: 0.72 cc/g
Presentation Notes
On the left we have the published uptake of N2 at 77K On the right we have our uptake from the same adsorption experiment we ran
N2 Adsorption Isotherms for V/Mg MOF
BET Surface Area: 1019 m2/g Pore Volume: 0.429 cc/g
BET Surface Area: 1011 m2/g Pore Volume: 0.50 cc/g
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
0 100 200 300 400 500 600 700 800 0
50
100
150
200
250
300
350
400
Presentation Notes
On the left we have the published uptake of N2 at 77K On the right we have our uptake from the same adsorption experiment we ran
Comparison to the Full Data
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
77 K
0 100 200 300 400 500 600 700 800 900 0
100
200
300
400
500
Presentation Notes
Our data lines up with where most of the MOFs have their uptakes lining up
CO2 Adsorption Isotherms for Fe/Mg
0 100 200 300 400 500 600 700 800 900 1000 0
20
40
60
80
100
120
140
160
180
200
220
Fe/Mg MOF CO2 Adsorption
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
Published Isotherm Experimental Isotherm
Presentation Notes
Our data produces a much lower CO2 uptake than the published data, even when going out to higher pressures
CO2 Adsorption Isotherms for V/Mg
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
0 100 200 300 400 500 600 700 800 900 1000 0
20
40
60
80
100
120
140
160
180
Presentation Notes
Our data produces a much lower CO2 uptake than the published data, even when going out to higher pressures
Heats of Adsorption V/Mg
Fe/Mg
Zhai, Q.-G.; Bu, X.; Mao, C.; Zhao, X.; Feng, P. Journal of the American Chemical Society 2016, 138 (8), 2524–2527.
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 0
10
20
30
40
50
60
70
80
90
100
Presentation Notes
Using our data and the virial equation we got this plot Fe/Mg is very close, but V/Mg was very different Lines up with the bulk of measurements published Remind Qst meaning
Diffraction Waves of angstrom scale diffract off of a crystal lattice and produce a distinct pattern
This diffraction is described in Bragg’s Law: 2 sin =
X-rays and thermal neutrons have the correct wavelength ranges X-rays: 1 Å - 2 Å Neutrons: 1.2 Å - 2.08 Å
Presenter
Presentation Notes
Since we see these discrepancies with the adsorptions, the next step is to check the structure Neutron Diffraction is the primary method I used for structural characterization this summer
Neutron Diffraction Why neutrons? With X-Ray diffraction there is difficulty seeing lighter elements when contrasted by metals Neutrons can detect these lighter elements in conjunction with the metals
High-Resolution Powder Diffractometer (BT-1) was used to confirm structure of synthesized MOFs
MOFs were dosed with stoichiometric amounts of CO2 during diffraction experiment
Presenter
Presentation Notes
NCNR is only place that does molar dosing in conjunction with neutron diffraction
Powder sample in vanadium canBT-1
Presenter
Presentation Notes
Photo of BT-1, Sample is placed in the middle Sample can is filled with powder and sealed. Attached to CCR system where temperature is controlled
CCR attached to CO2 line for gas dosingSample in aluminum can—ready for the beam
Presenter
Presentation Notes
Sample is encased in aluminum to seal it Chamber is put under vacuum—cooled with liquid helium ~7K A set volume is filled to a specific pressure then opened to the system to be adsorbed by the MOF
Diffraction Patterns of Fe/Mg MOF
0 5 10 15 20 25 30 35 40 0
500
1000
1500
2000
2500
3000
3500
4000
In te
ns ity
(C ou
nt s)
2θ (o)
2 Eq Dose 1 Eq Dose 2/3 Eq Dose 1/3 Eq Dose No CO2
Presenter
Presentation Notes
These are the patterns produced by BT-1 for the Fe/Mg MOF Key difference spotted with the first peak that gets bigger at 1 eq dose and 2 eq dose
Diffraction Patterns of In/Mg MOF
0 5 10 15 20 25 30 35 40 0
1000
2000
3000
4000
5000
6000
7000
In te
ns ity
(C ou
nt s)
2θ (o)
1 Eq Dose 2/3 Eq Dose 1/3 Eq Dose No CO2
Presenter
Presentation Notes
These are the patterns for the In/Mg MOF Disappearance of some small peaks
Bare Structure Fit of Fe/Mg MOF
0 10 20 30 40 50 60 70 80 90 100 0
2000
4000
6000
8000
10000
12000
14000
16000
0 20 40 60 80 100 120 140 0
2000
4000
6000
8000
10000
12000
14000
16000
Presentation Notes
From this we get the structure with CO2 and Water Multiple Orientations of water Generally describe more 1/3 Dose
CO2
H2O
Presenter
Presentation Notes
Structure w/ CO2 and water CO2 displaces water Hydrogen bonding interactions
Conclusions and Future Work Data derived from adsorption isotherms fall in the expected range for open metal site MOFs
Structure is correct—Right materials are produced
CO2 binds to open metal site, displacing water molecule
Further studies into the effects of water on adsorption
Inductively Coupled Plasma-Optical Emission Spectroscopy to determine metallic ratios
More structural and isotherm data
Acknowledgements Mentors: Ben Trump & Craig Brown
Prof. Eric Bloch, Eric Gosselin
Dr. Taner Yildirim
Center for High Resolution Neutron Scattering
All the NCNR SURFers
Background
Comparison to the Full Data
CO2 Adsorption Isotherms for Fe/Mg
CO2 Adsorption Isotherms for V/Mg
Heats of Adsorption
Bare Structure Fit of Fe/Mg MOF
Preliminary Refined Structure with CO2
Slide Number 22
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