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The groups of Christopher Jones and David Sholl recently published a paper on the effect of humidity on capturing H2S from multicomponent biogas streams using solid-supported hindered and unhindered amines. Understanding how different amine species (hindered/unhindered) behave in presence of water throughout H2S capture processes can help discern underlying structural effects of different amine species, which gives insights into further optimization. Key findings from the work include our observation that the presence of H2O led to better H2S capture performances (i.e., capacity and H2S/CO2 selectivity). This is based on H2O led to a proton transfer mechanism during the H2S-amine interaction, giving rise to preferred H2S binding (over CO2) to the amine sites driven by differences in kinetic energy barriers. as studied by DFT calculations. Also, based on our observation via solid-state NMR experiments, amine-appended solid sorbents were stable after multicycle capture-regeneration steps. A link to the paper can be found
The groups of Christopher Jones and Sophia Hayes published a paper on elucidating the formation of bicarbonate species during CO2 capture within solid amine sorbents in which dimethylaminopropylsilane (DMAPS) and aminopropylsilane (APS) pendant molecules were grafted onto the pore surface of SBA-15. Although the chemistry of CO2-amine interactions for a free liquid phase are well-understood, solid sorbents may exhibit different behavior due to steric hindrance and mass transfer limitations, and therefore understanding how CO2 interacts with solid amine sorbents is crucial. Key findings from the work derive from using proper solid-state NMR methods. Bloch decay (“pulse-acquire”) sequence (with 1H coupling) combined with 13C-1H HETCOR NMR indicated the formation of bicarbonate species that could not be detected by conventional 13C CPMAS NMR. A link to the paper can be found [https://pubs.acs.org/doi/10.1021/jacs.8b04520].
The groups of Christopher Jones and Bobby Sumpter published a paper on understanding the dynamics of poly(ethyleneimine) (PEI) confined in mesoporous SBA-15 via quasi-elastic neutron scattering (QENS) combined with molecular dynamic simulations*. PEI dynamics are crucial as they dictate CO2 uptake performance such as capacities and uptake rates. Key findings from the work include the observation that dynamics of PEI was impeded by both physical confinement within the pores and attractive interactions with the pore surface. And understanding how PEI behaves under various circumstances can provide insights into further development of this commercially important class of sorbents for more effective CO2 capture. A link to the paper can be found
Baltrusaitis group in collaboration with Oak Ridge National Laboratory and the University of New Mexico recently published work on subnanometer iron catalysts supported on Al2O3 as sulfur tolerant catalysts for propane dehydrogenation. This research indicates that promoted alumina can be used as an earth-abundant catalyst for upgrading alkanes in sour natural gas. The major findings include (1) Fe could be fully dispersed on the support in sulfide form and (2) the highest activity with 52% propane conversion and ∼99% propylene selectivity at 560 °C. The link to the paper can be found [https://pubs.acs.org/doi/full/10.1021/acsanm.1c01366].
The Page and Nair groups recently published a paper on Modeling of ZIF-8 total scattering data. The methodologies developed are a step forward in understanding structural disorder in MOF materials. In order to properly model both the local and extended structure, a modeling scheme was developed which models sub-units of the structure with varying disorder, including the rigid linker molecule, the individual metal-linker complex, and the extended structure of the MOF. A stacking fault model along the  direction gave poor agreement with diffraction data, suggesting these defects are not present in ZIF-8. To properly capture peak broadening in a family of lattice planes in reciprocal space, a positional fluctuation along the  direction must be included in the model. The positional fluctuation reflects a low and anisotropic shear modulus of the material. A link to the paper can be found [https://doi.org/10.1107/S1600576721002843].
PhD students Rishi Gurnani and Zhenzi Yu, working with Prof. Rampi Ramprasad and Prof. David Sholl recently published a paper in Chemistry of Materials on machine learning methods for predicting gas uptake in metal-organic frameworks (MOFs). The number of MOFs and related materials that exist is far larger than that can be explored with direct experiments, so machine learning offers a powerful tool to rapidly explore this large search space. A key aspect of the methods used by Gurnani et al. is that they are interpretable, meaning that in addition to making predictions about specific materials they also yield information about general structure-property relationships. The link to the paper can be found
The groups of Dave Dixon and Israel Wachs recently published a paper on Selective Catalytic Reduction of NOx with NH3 to N2 and H2O by TiO2- supported vanadium oxide catalysts. SCR is important because this technology reduces emissions of acidic NOx from power plants and diesel engines. Key findings from the work include (1) Electronic structure calculations at the density functional theory were performed on neutral and protonated monomer and dimer clusters of vanadium oxide (VxOy) on a cluster model of a TiO2 support based on experimental 51V NMR measurements. (2) The first step is Lewis acid–base addition of NH3 to a vanadium site for the neutral surface and formation of an “NH4+” species on the protonated surface. (3) NO reactions with the surface ammonia species to form the reaction intermediate H2NO that desorbs and then undergoes gas-phase rearrangements to form the final products of N2 + H2O. (4) The predicted SCR reaction pathways are complex and consistent with the available experimental data. A link to the paper can be found [https://doi.org/10.1021/acscatal.0c03693].
The groups of Rimsza from Sandia National Laboratories and Dixon from the University of Alabama recently published a paper on predicting acid gas adsorption in rare earth DOBDC metal-organic frameworks (MOFs) through the application of complementary computational methods. Predicting acid gas adsorption is important because it guides design of new materials with adsorption properties based on gas-framework interactions. Key findings from this work include that the presence of structural linkers increases binding between the guest molecule and the MOF and that the gas binds to the metal center via physisorption. A link to the paper can be found [https://pubs.acs.org/doi/abs/10.1021/acs.jpcc.0c08282].
The groups of Page, Wu and Sumpter recently published a paper on revealing the nature of oxygen vacancies in ceria catalysts and their changes upon interaction with sulfur dioxide via in situ neutron scattering. Key findings from the work include (1) In addition to the bulk Frenkel-type oxygen vacancies, a partially reduced surface ceria phase with long-range oxygen-vacancy ordering (Ce3O5+x) has been observed experimentally for the first time with neutron scattering, pair distribution function and aided by density functional theory calculations. (2) The quantity of both surface and bulk defects of ceria is dependent on the surface morphology (rods vs. cubes). (3) A drastic decrease of the surface vacancies in the ceria nanocrystals. is observed upon exposure to SO2 while the bulk defects are only slightly impacted, suggesting surface defects are key for the redox properties of ceria catalysts. A link to the paper can be found [https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.1c00156].
The groups of Nenoff from Sandia and Hayes from Washington University St. Louis recently published a paper on Mg-MOF-74 and competitive binding between SOx and H2O. Mg-MOF-74 and competitive binding between SOx and H2O is important because of we were able to establish the combine mixed gas adsorption studies with solid state NMR to elucidate the preferential binding of the acid gas SOx versus the more concentrated water in the stream. Key findings from the work include SOx preferentially binds to the oxophilic metal site of the MOF framework over H2O, and the SOx loaded MOF is stable for 14+ weeks. A link to the paper can be found [https://pubs.acs.org/doi/10.1021/acsami.0c21298].
PhD student Rishi Gurnani, working with Prof. Rampi Ramprasad recently published a paper in Chemistry of Materials aimed at solving the inverse problem for polymer design using artificial intelligence (AI). The AI platform created by Gurnani et al. was found capable of designing novel, realistic, and valuable polymer structures after training on past data. 93% of all AI-designed polymers were found to be chemically valid. Further, Density Functional Theory calculations showed good agreement with the AI. Ultimately, 10 AI-designed polymers were suggested for use in dielectrics subject to extreme conditions. Next, the AI will be aimed at the design of gas-separation membranes resistant to aging. A link to the paper can be found [https://pubs.acs.org/doi/abs/10.1021/acs.chemmater.1c02061].”
The Schmidt and Nair groups recently explored the origins of the unique acid gas stability of ZIF-71. Due to the vulnerability of ZIFs in acidic environment, understanding their stability is essential for the design of acid-gas resistant materials for potential industrial applications. We integrated QM/MM methods and statistical mechanics models to calculate the thermally averaged defect formation rate in ZIF-8 and ZIF-71. Our analysis reveals that differing stability of the two materials is determined by the distribution of acid gas molecules rather than merely their “intrinsic” reactivity, resulting in differing degradation mechanism. As a result, the average defect formation rate in ZIF-71 is ~9 times lower than ZIF-8, leading to the conclusion that the observed experimental stability of this material rises from kinetic effects.
A link to the paper can be found at [https://pubs.acs.org/doi/10.1021/jacs.1c06321].
Machine Learning Advances Materials for Separations, Adsorption, and Catalysis
UNCAGE-ME sixth All Hands meeting was virtually. Students, postdocs attend the virtual meeting. At the meeting, awards were presented for this year’s Best Research Papers from the Center. Zachary Lee won the Best Paper Award "Predicting the Formation of Sulfur-Based Bronsted Acids from the Reactions of SOx with H2O and H2S", and Lohit Sharma won for paper “" Inhibitor, co-catalyst, or co-reactant? Probing the different roles of H2S during CO2 hydrogenation on MoS2 catalyst". Both awardees gave a presentation on their work at the meeting. Awardees were presented for this year’s Best Research papers from the Center.
Sophia Hayes giving testimony on "critical elements" --- specifically on the helium shortage. https://science.house.gov/hearings/research-and-innovation-to-address-the-critical-materials-challenge.
Hope on Climate Change from a Bold and Brilliant Woman at TEDxGatewayArch: http://alivemag.com/hope-on-climate-change-from-a-bold-and-brilliant-woman-at-tedxgatewayarch/ from Sophia Hayes, Washington University.
This youtube video is related to Lehigh University recent manuscript and represent work cited: https://www.youtube.com/watch?v=WaLmsjwaHL8
We are eager to share the latest issue of Frontiers in Energy Research http://www.energyfrontier.us/newsletter.
The latest issue of Frontiers in Energy Research features UNCAGE-ME. Your team's research appears in Artificial Intelligence to Solve Important Problems in Energy and Climate Change (https://www.energyfrontier.us/content/artificial-intelligence-solve-important-problems-energy-and-climate-change).
UNCAGE-ME held its fifth All Hands Meeting this month on the GT campus. Students, postdocs and PI’s from the Center attended this two-day event. At the meeting, awards were presented for this year’s Best Research Papers from the Center. Jay Joshi won the Best Paper Award for his paper “Structured Growth of metal-Organic Framework MIL-53(AI) from Solid Aluminum Carbide Presursor”, and Souryadeep Bhattacharyya won for his paper "Stability of Zeolitic Imidazolate Framework in NO2". Both awardees gave a presentation at the meeting on their work. Additionally, the students and postdocs participated in breakout discussions.
Dr. Israel E. Wachs, the G. Whitney Snyder Professor of Chemical and Biomolecular Engineering at Lehigh University's P.C. Rossin College of Engineering and Applied Science has been elected as a fellow of the National Academy of Inventors (NAI). The NAI describes the honor as "the highest professional distinction accorded to academic inventors who have demonstrated a prolific spirit of innovation in creating or facilitating outstanding inventions that have made a tangible impact on quality of life, economic development and the welfare of society."
The latest issue of Frontiers in Energy Research features UNCAGE-ME. Your team's research appears in Scientists Discover Stable Material for Sulfur Dioxide Capture (https://www.energyfrontier.us/content/scientists-discover-stable-material-sulfur-dioxide-capture).
Rochelle Moses has joined UNCAGE-ME as the Program Manager for the Center.
DOE Awards $100 Million for Energy Frontier Research Centers. UNCAGE-ME EFRC is among 22 new and 9 renewed EFRCs to be awarded an EFRC grant. We are excited to continue our research mission for the next four years!
Congratulations to Professors Ryan P. Lively and Christopher W. Jones as the winners of the 2018 Energy & Fuels Joint Award for Excellence in Publication for the article “SOx/NOx Removal from Flue Gas Streams by Solid Adsorbents: A Review of Current Challenges and Future Directions”. Energy & Fuels and the ACS Division of Energy & Fuels sponsor this annual award, which honors an outstanding article published in the journal within the past five years.
Professor Sophia Hayes launched a K-12 teacher discussion group called the "Blue Skies Discussion Group" through Washington University in Saint Louis. This group engages with teachers in the St. Louis and central Illinois area who want to expand their knowledge of environmental and energy issues. A detailed description and list of activities can be found here: https://schoolpartnership.wustl.edu/events/blue-skies-discussion-group/.
We are excited to share that the latest issue of Frontiers in Energy Research features UNCAGE-ME. Our team's research appears in The Importance of Being Defective (http://www.energyfrontier.us/content/importance-being-defective).
UNCAGE-ME held its fourth All Hands Meeting this month on the GT campus. Students, postdocs and PI’s from the Center attended this two-day event. At the meeting, awards were presented for this year’s Best Research Paper from the Center. Guanghui Zhu won the Best Paper Award for his paper “Formation Mechanisms and Defect Engineering of Imine-Based Porous Organic Cages”, while Krishna Jayachandrababu received the runner-up award for his paper "Recovery of Acid-Gas-Degraded Zeolitic Imidazolate Frameworks by Solvent-Assisted Crystal Redemption (SACRed)". Both awardees gave a presentation at the meeting on their work. Additionally, the students and postdocs participated in team building activities.
Jonas Baltrusaitis' recent contribution to Catalysis Science & Technology has been highlighted as a HOT manuscript in 2017. More information is available here, and the publication can be found here.
The poster presentation “Tungsten Oxide Promotion of SCR of NOx with NH3 by Titania-Supported Vanadium Oxide Catalysts", by Jun-Kun Lai, Minghui Zhu, Michael E. Ford, and Israel E. Wachs was selected as the Best Poster at the 9th International Symposium on Group Five Elements held in Delhi, India on Nov. 22-24, 2017. Professor Wachs also presented a plenary lecture entitled "Reaction Mechanism, Surface Intermediates and Kinetics for SCR of NOx with NH3 by Titania-Supported Vanadium Oxide Catalysts." More details of this symposium can be found at the following link: http://www.iitk.ac.in/gviitk/