a DoE Energy Frontier Research Center

Selective Gas Capture via Kinetic Trapping

The burning of carbon based fossil-fuels and the consequent release of carbon dioxide in the atmosphere poses a threat to the environment. Capture and sequestration of CO2 from a flue-gas mixture is therefore a pressing need. Adsorbents like metal-organic frameworks (MOFs) are used for this purpose, but gas uptake processes rely on equilibrium conditions, severely restricting the parameter space of conditions and materials available to industry. Furthermore, nonequilibrium aspects of gas capture in MOFs remains unexplored. Here, using a simple statistical mechanical model of gas diffusion and binding, parameterized by quantum mechanical data, we show that selective gas capture in MOFs can be effected under nonequilibrium conditions. Employing ideas of statistical mechanics, we uncover the emergent gas separation mechanism that arises due to different mobilities of different gas types within a crowded framework. We predict optimum nonequilibrium strategies for effective gas uptake. Our simulation study provides a new perspective on the problem of gas capture, and identifies a path toward using previously discounted or new materials and conditions to achieve it.
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An In Situ One-Pot Synthetic Approach towards Multivariate Zirconium MOFs

Integrating multi-functionality into stable metal-organic frameworks (MOFs) has attracted growing attention as it plays a critical role in realizing the potential of MOFs for a wide range of applications. This work shows that tetratopic porphyrin ligands can be incorporated, rather than simply encapsulated, into UiO-66 through a one-pot, thermodynamically controlled synthesis from mixed ligands. Control experiments demonstrated that the number of carboxylic groups plays a vital role in integrating TCPP into UiO-66, very likely through coordination to Zr6 clusters during the synthesis, generating defects and larger pores to allow the residence of TCPP in the framework. Through modifying BDC moieties and porphyrin moieties, 49 MOFs with multi-functionalities were obtained. This strategy goes beyond the limit of conventional mixed-ligand strategies and post-synthetic modifications and expands the diversity of functionality for stable MOFs modification, holding great potential for exploring the applications of MOFs extensively.
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Reversible CO Scavenging via Adsorbate-Dependent Spin Transitions in an Fe(II)-Triazolate Metal-Organic Framework

A material that is able to bind CO selectively and reversibly at low pressures and reasonable temperatures is desirable for many of these applications. Porous materials have been explored as possible adsorbents, but thus far face selectivity issues, have low capacities at low pressures, or adsorb CO so strongly that it is irreversible. In this work, we have synthesized a new microporous material, Fe-BTTri, that binds CO at extremely low pressures, allowing for potential scavenging of CO at these low pressures. This material is also able to release the CO, allowing for a fully regenerable material. Fe-BTTri shows unprecedented selectivity for CO over H2, N2, and even CO2, which typically competes with CO adsorption in porous materials. We envision that this spin transition mechanism can be applied to other gases separations for further improvements in selective adsorbents.
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Enhanced Separation and Mitigated Plasticization in Membranes using Metal-Organic Framework Nanoparticles

The implementation of membranes for ethylene/ethane separations is challenging due to low membrane selectivities under both pure and mixed-gas conditions. Traditional approaches of compositing membranes do not yield improved ethylene/ethane performance, because they rely on a size-sieving based mechanism. Here, the improved adsorption selectivity in M2(dobdc) nanoparticles is instead leveraged to improve membrane permselectivity. The open-metal sites in the metal-organic framework pores selectively adsorb ethylene, increasing the total concentration of ethylene in the film relative to ethane. This leads to an increase in permselectivity as well as permeability in the case of Ni2(dobdc) and Co2(dobdc), while the permeability greatly increases in the case of Mg2(dobdc) and Mn2(dobdc) but a slight decrease in selectivity is observed.
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Systematic Tuning and Multi-Functionalization of Covalent Organic Polymers for Enhanced Carbon Capture

A systematic strategy is proposed for preparing multi-functionalized covalent organic polymers (COPs) using the efficient Ullmann cross-coupling reaction. Using this strategy, 17 novel multiblock COPs were synthesized with finely-tuned porosities from a core tetrahedral linker, tetrakis(4-bromophenyl) methane (TBM), and a variety of aromatic linear, trigonal, and even tetragonal linkers. The COPs synthesized in this work have remarkably high porosities and hydrothermal stabilities, which are critical for the adoption of these materials for industrial applications. By tailoring the length and geometry of building blocks, it is possible to tune the BET specific surface areas (SSAs) and pore volumes of these COPs. As a result, the material COP-20 (composed of TBM + DB-OH) has been synthesized with the largest measured pore volume in the field of porous organic materials (3.5 cm3·g-1).
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Layered ZIF-Polymer Membranes Through On-Polymer Chemical Transformations of Colloidal Nanocrystal Films

Here it is shown that sub-micron coatings of zeolitic imidazolate frameworks (ZIFs) and even ZIF-ZIF bilayers can be grown directly on polymers of intrinsic microporosity from zinc oxide (ZnO) nanocrystal precursor films, yielding a new class of all-microporous layered hybrids. The ZnO-to-ZIF chemical transformation proceeded in less than 30 min under microwave conditions using a solution of the imidazole ligand in N,N-dimethylformamide (DMF), water, or mixtures thereof. By varying the ratio of DMF to water, it was possible to control the morphology of the ZIF-on-polymer from isolated crystallites to continuous films.
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Covalent Organic Frameworks Comprising Cobalt Porphyrins for Catalytic CO2 Reduction in Water

In this work, the concepts of molecular homogenous and heterogeneous catalysis were merged as illustrated by incorporation of molecular CO2 reduction catalysts into the backbone of a spatially well-defined covalent organic framework. This prototype system gives exceptionally high activity (turnover number 290,000, and turnover frequency 9,400 h-1) as well as selectivity over competing proton reduction even in pH 7 water. Covalent organic frameworks (COFs) were chosen instead of the more intensively studied metal organic frameworks (MOFs) owing to the high degree of conjugation and pi-pi stacking between layers in the former, which result in higher charge-carrier mobilities than found in MOFs.
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Novel CO2 Binding Mechanism Determined Via in-situ X-ray Absorption Spectroscopy & Theory

X-ray absorption spectroscopy (XAS) probes the local partial density of molecular orbital states around distinct absorbing atoms, and thus provides unique information about the location and chemical nature of the CO2 adsorption process in metal-organic frameworks (MOFs). The figure shows absorption spectra of the nitrogen and oxygen in diamine-appended Mg2(dobpdc); in each case the blue and red spectra represent the MOF without and with adsorbed CO2 present, respectively. Arrows indicate significant spectral changes. First principles theoretical spectra for distinct CO2 adsorption models were also calculated. Three different models had been proposed for the adsorption of CO2 in this MOF, and by comparison of measured and computed spectra for these models we learned that only the insertion model accounts for the observed spectral changes.
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About the CGS


Who We Are

The Center for Gas Separations is one of 32 Energy Frontier Research Centers funded by the Department of Energy to conduct fundamental research that addresses the five Basic Energy Sciences Grand Challenges:

  1. How do we control material processes at the level of electrons?
  2. How do we design and perfect atom- and energy-efficient synthesis of revolutionary new forms of matter with tailored properties?
  3. How do remarkable properties of matter emerge from complex correlations of the atomic or electronic constituents and how can we control these properties?
  4. How can we master energy and information on the nanoscale to create new technologies with capabilities rivaling those of living things?
  5. How do we characterize and control matter away -especially very far away- from equilibrium?

The Center is made up of researchers across the US, at the University of California, Berkeley (lead institution), Lawrence Berkeley National Lab, Texas A&M University, University of Minnesota, the National Energy Technology Laboratory, and the National Institute of Standards and Technology.


What We Do

Although it is challenging to calculate the energy used by all chemical separation processes, the best estimates indicate that they account for 10-15% of the energy consumed globally. Some of the largest offenders are the purification of oxygen (O2, 91% of energy input is for separating N2), petroleum refining (>50% energy expended is for separations), and the separation of carbon dioxide (CO2) from H2 necessary for ammonia production (25% of energy consumed). In the US alone, separations account for an even greater ~22% of the total national energy input. Furthermore, when faced with climate change resulting from continually-increasing anthropogenic CO2 emissions and the corresponding necessity of large-scale carbon capture and storage, the cost of separations is expected to increase significantly. Reducing the total energy costs of separations would therefore contribute substantially to minimizing wasteful energy consumption globally.

To address this need, the primary goal within the Center for Gas Separations (CGS) is to tailor-make novel materials for highly efficient gas separations, with an emphasis on adsorbents that are highly selective for CO2 capture. This strategy addresses the 2nd Grand Challenge and requires a fundamental understanding of materials properties, molecular interactions, and the design of adsorbents tuned precisely for interactions with specific gases.

Announcements


Date  
June
2016
2016 All-Hands Meeting
Date: November 8-9, 2016
Location: DoubleTree Hilton at the Berkeley Marina
Reminder: November 8th is Election Day. Don't forget to make arrangements to vote by mail before arriving at the meeting!
April
2015
Materials Science: The Hole Story (Nature: News Feature, 520, 148-150, April 8, 2015)
March
2015
Materials Chemistry: Cooperative Carbon Capture (Nature News & Views, 519, 294-295, March 19, 2015)
March
2015
Porous Crystal Supersuckers Capture Carbon (IEEE Spectrum, March 18, 2015)
March
2015
New Material Captures Carbon at Half the Energy Cost (Phys.org, March 11, 2015)
March
2015
New Material Captures Carbon at Half the Energy Cost (Science Daily, March 11, 2015)
March
2015
New Material Captures Carbon at Half the Energy Cost (Scicasts, March 11, 2015)
March
2015
A Better Way To Scrub CO2 (Science 2.0, March 19, 2015)
March
2015
A Better Way of Scrubbing CO2 (Newswise, March 17, 2015)
March
2015
A Better Way of Scrubbing CO2 (Lab Manager, March 19, 2015)
March
2015
Researchers Triple CO2-Scrubbing Capacity of MOFs by Appending a Diamine Molecule (Azonano, March 18, 2015)
March
2015
A Better Way of Scrubbing CO2 (Nanowerk, March 17, 2015)
March
2015
A Better Way of Scrubbing CO2 (EurekAlert! March 17, 2015)
March
2015
A Better Way of Scrubbing Carbon Dioxide (R&D Mag, March 17, 2015)
March
2015
Cooperative Insertion of CO2 in Diamine-appended Metal-organic Frameworks (Bioportfolio, March 11, 2015)
March
2015
A Better Way of Scrubbing CO2 (Innovations Report, March 18, 2015)
March
2015
New Material Captures Carbon at Half the Energy Cost (Health Medicinet, March 2015)
March
2015
Material Captures Carbon at Half the Energy Cost (Product Design & Development, March 13, 2015)
March
2015
Cooperative Capture (Nature podcast interview of Jeff Long on work reported in 3/12/15 Nature article)
March
2015
The Proof Is in the Pores (EFRC Newsletter, March 2015)
March
2015
Predicting Cheaper Routes for Carbon Capture (EFRC Newsletter, March 2015)
December
2014
Cover of Chemical Science (Chem. Sci., Dec. 2014)
November
2014
Playing Catch and Release with Molecules (Frontiers in Energy Research, Nov. 2014)
October
2014
New Carbon Capture Method is the Best of Both Worlds (Nature World News, Oct. 2014)
October
2014
Un captage de carbone (encore) plus rentable et plus efficace ? (Enerzine, Oct. 2014)
October
2014
MOF Slurry-Based Process May Revolutionize Carbon Capture (Azonano, Oct. 2014)
October
2014
A Cost-effective and Energy-efficient Approach to Carbon Capture (Science Newsline, Oct. 2014)
October
2014
A Cost-effective and Energy-efficient Approach to Carbon Capture (Phys.org, Oct. 2014)
October
2014
New 'Slurry' Could Make Carbon Capture More Efficient (Climate Central, Oct. 2014)
October
2014
A Cost-effective and Energy-efficient Approach to Carbon Capture (e! Science News, Oct. 2014)
October
2014
A Cost-effective and Energy-efficient Approach to Carbon Capture (Science Daily, Oct. 2014)
October
2014
A Cost-effective and Energy-efficient Approach to Carbon Capture (USA News, Oct. 2014)
October
2014
A Cost-effective and Energy-efficient Approach to Carbon Capture with MOFs (Nanowerk, Oct. 2014)
September
2014
New Sorbents for Greener Cooling (C&EN, Sept. 2014)
June
2014
An Inside Look at a MOF in Action (ALS Highlight, June 2014)
April
2014
MOFs (MRS-TV video, April 2014)
December
2013
Research Highlight: Cage Calculations (Nature Chemistry, Dec. 2013)
August
2013
New method predicts adsorption in carbon dioxide-scrubbing materials (R&D Magazine, Aug. 2013)
August
2013
Cover of Advanced Materials (Adv. Mat., Aug. 2013)
June
2013
Cover of the Journal of Physical Chemistry C (J. Phys. Chem. C, June 2013)
May
2013
Material That Sorts Molecules by Shape Could Lower the Price of Gas (MIT Technology Review, May 2013)
April
2013
Researchers discover materials to transform methane into fuel (The Daily Californian, April 2013)
April
2013
Methane-gobbling material found, scientists say (NBC News, April 2013)
April
2013
Inside back cover of Angewandte Chemie (Angewandte Chemie, April 2013)
December
2012
MOFiosos: Berkeley scientists make carbon a structure it cannot refuse (Berkeley Science Review, Dec. 2012)
November
2012
Cover of ChemPhysChem (ChemPhysChem, Nov. 2012)
October
2012
Nanosolutions for Grand Challenges (EFRC Newsletter, Oct. 2012)
October
2012
News and Views in Nature Chemistry: Force fields for carbon capture (Nature Chemistry, Oct. 2012)
October
2012
Cover picture on Angewandte Chemie (Angewandte Chemie, Oct. 2012)
September
2012
Biomimetic And Extreme Surface-Area Frameworks (C&EN, Sept. 2012)
August
2012
Cover of PCCP (PCCP, Aug. 2012)
May
2012
Computer Model Pinpoints Prime Materials for Efficient Carbon Capture (Science Daily, May 2012)
May
2012
New Materials could Reduce Parasitic Load of CO2 Capture by up to 40%, Researchers Say (GHG Monitor, May 2012)
May
2012
New Materials Could Cut Parasitic Energy Costs for CO2 Capture by up to 30-40% (Green Car Congress, May 2012)
April
2012
A Step Up for Separating Hydrocarbons (C&EN, April 2012)
March
2012
New Material Cuts Energy Costs of Separating Gas for Plastics and Fuels (e! Science News, March 2012)
March
2012
Cutting the Cost for Commercial Gas Purification -Theory Leads the Way for a Materials Solution (DOE-BES highlight, March 2012)
March
2012
Carbon Dioxide Catchers (Nanowerk, March 2012)
August
2011
Inside front cover of Advanced Materials (Advanced Materialds, Aug. 2011)
October
2010
Structure of the Week - # 10 October 25, 2010 (ACS, Oct. 2010)
September
2011
Metal Organic Frameworks (CEN Online video, Sept. 2011)
July
2010
Carbon Smackdown: Carbon Capture (Berkeley Lab video, July 2010)
May
2010
Hunt for Improved Carbon Capture Picks up Speed (Berkeley Lab video, May 2010)
February
2010
Carbon Cycle 2.0: Carbon Capture (Berkeley Lab video, Feb. 2010)