A5079771471- Zeolite Catalysis and Synthesis
- Metal-Organic Frameworks: Synthesis and Applications
- Crystallization and Solubility Studies
- Carbon Dioxide Capture Technologies
- Mesoporous Materials and Catalysis
- X-ray Diffraction in Crystallography
- Advanced NMR Techniques and Applications
- Magnetism in coordination complexes
- Crystallography and molecular interactions
- Covalent Organic Framework Applications
- Chemical Synthesis and Characterization
- Phase Equilibria and Thermodynamics
- Membrane Separation and Gas Transport
- Lanthanide and Transition Metal Complexes
- Luminescence and Fluorescent Materials
- Advanced Thermoelectric Materials and Devices
- NMR spectroscopy and applications
ExxonMobil (United States)
2011-2021
The discovery of new materials for separating ethylene from ethane by adsorption, instead using cryogenic distillation, is a key milestone molecular separations because the multiple and widely extended uses these molecules in industry. This technique has potential to provide tremendous energy savings when compared with currently used distillation process produced through steam cracking. Here we describe synthesis structural determination flexible pure silica zeolite (ITQ-55). material can...
We demonstrate a new approach to develop transferable force fields describing molecular adsorption in zeolites by combining dispersion-corrected density functional theory (DFT) calculations and classical atomistic simulations. This is illustrated with the of CO2 zeolites. Multiple DFT methods were tested for sodium-exchanged ferrierite. The DFT-D2 was found give best agreement high level quantum chemistry results experimental data. A field siliceous then developed on basis hundreds that...
The development of accurate force fields is vital for predicting adsorption in porous materials. Previously, we introduced a first principles-based transferable field CO2 siliceous zeolites (Fang et al., J. Phys. Chem. C, 2012, 116, 10692). In this study, extend our approach to cationic which possess more complex structures. Na-exchanged are chosen demonstrating the approach. These methods account several structural complexities including Al distribution, cation positions and mobility, all...
Pyridine-modified COF-10 exhibits enhanced stability in humid air relative to un-modified COF-10. Solid state NMR and computational studies were used probe the nature of pyridine interactions with framework. We propose two models for pyridine-framework different stabilities.
We have found that the 3D zeolitic imidazolate framework ZIF-7 exhibits far more complex behavior in response to adsorption of guest molecules and changes temperature than previously thought. believe this arises from existence different polymorphs types sites. report undergoes a displacive, nondestructive phase change upon heating above ∼700 °C vacuum, or ∼500 CO2 N2. This is first example temperature-driven ZIF frameworks. predicted occurrence high-temperature transition on basis...
Heat of adsorption is an important factor in determining the utility a porous material for gas separation and storage applications. Although theoretically heat can depend on temperature, it common practice to assume that this dependence so weak be ignored. In paper, we challenge wisdom. We simulated isotherms heats small molecules (CO2, CH4, N2) reference siliceous (LTA, CHA, MFI) cation-exchanged (LTA-4A, Na-LTA Si/Al = 2,5) zeolites found very significant temperature isosteric CO2 at low...
A novel borosilicate zeolite structure was solved from rotation electron diffraction data and preferential boron positions could also be identified.
A new pressure‐swing frequency response (PSFR) method has been developed to study mass transfer in adsorption systems as a function of temperature and pressure, from −70 180°C, up 7 bar. New in‐phase out‐of‐phase functions have derived for the PSFR general way allow information extracted it independent whether system is operated batch volume swing or flow‐through pressure mode. mathematical model that considers distribution diffusion rates introduced account diffusive transport heterogeneous...
Zeolitic imidazolate frameworks (ZIFs), a unique subclass of metal‐organic (MOFs) recently reported by Yaghi group and others, are attracting worldwide attention. Our systematic work on the adsorption molecular transport in ZIFs has revealed some properties these new materials that could not have been anticipated from standard structural characterization results. More specifically, rearrangement linkers (and cases, framework structure) driven adsorbate‐adsorbent interaction causes window...
A new aluminosilicate zeolite, denoted EMM-37, with a 3D small pore channel system, has been synthesized using diquaternary ammonium molecule as the structure directing agent (SDA) and metakaolin aluminum source. The structures of both as-made calcined forms EMM-37 were solved refined continuous rotation electron diffraction (cRED) data. cRED is powerful method for collection data from submicron- nanosized crystals, which allows successful solution refinement complex in symmetry low P1̅.
The structural flexibility of ZIF-7 is controlled via a mixed-linker approach resulting in modified adsorption properties tunable across 2 orders magnitude step pressure while maintaining the structure throughout compositional range.
Zeolitic imidazolate frameworks (ZIFs), a unique subclass of metal‐organic (MOFs) recently reported by Yaghi group and others, are attracting worldwide attention. Our systematic work on the adsorption molecular transport in ZIFs has revealed some properties these new materials that could not have been anticipated from standard structural characterization results. More specifically, rearrangement linkers (and cases, framework structure) driven adsorbate‐adsorbent interaction causes window...