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At least 1,351 records · Page 75
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Mechanistic Studies of Oxidative Degradation in Diamine-Appended Metal–Organic Frameworks Exhibiting Cooperative CO 2 Capture

Understanding the impact of O 2 during a carbon capture process is vital for designing robust, cost-effective materials for carrying it out. However, mechanistic studies of the O 2 -induced degradation of materials are not easily undertaken owing to the complex sequential reaction pathways that arise. Here, we report comprehensive mechanistic investigations of the O 2 -induced degradation of diamine-appended metal−organic frameworks (MOFs) exhibiting cooperative CO 2 adsorption. Oxygen exposure experiments were performed on seven different diamine-appended MOFs, including e-2−Mg 2 (dobpdc) (e-2 = N-ethylethylenediamine, dobpdc 4− = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), under various temperatures and O 2 pressures. These experiments show that diamine degradation inhibits CO 2 chemisorption and that the degradation rate is significantly influenced by the diamine structure. In contrast, the parent frameworks remain essentially intact upon O 2 exposure. Detailed characterization of O 2 -exposed e-2−Mg 2 (dobpdc) revealed the formation of various degradation products, including acetaldehyde, carbon dioxide, water, ethylamine, and other aldehyde- and imine-containing species. Together, these observations suggest that diamine degradation occurs via C−N bond cleavage through pathways involving C-centered radicals. Furthermore, computational evaluation of the initiation and propagation pathways for amine degradation in diamine-appended MOFs indicates that (i) degradation is likely initiated by OH • , (ii) carbon-centered radicals generated via radical transfer reactions react with O 2 , leading to amine degradation, and (iii) the ratelimiting step of the degradation reactions likely involves O−O bond cleavage. Overall, these mechanistic insights could inform strategies for mitigating O 2 -induced amine degradation in next-generation carbon capture technologies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Photo-DAC: Light-Driven Ambient-Temperature Direct Air Capture by a Photobase

Direct air capture (DAC) may reduce atmospheric CO 2 concentrations to preindustrial levels, yet the high energies and temperatures involved in current DAC technologies hinder large-scale deployment. In the case of aqueous-based CO 2 absorbents, a large energetic penalty is associated with heating and boiling off water, as required for thermally driven solvent regeneration. This could be avoided via photochemically driven pH swings involving photoacids or photobases, and harnessing abundant and renewable solar energy, though efficient solvent regeneration and recycling in a realistic multicycle DAC process remains challenging. Herein, we report a photochemically driven DAC process (photo-DAC) in which atmospheric CO 2 capture by an aqueous glycylglycine (GlyGly) solution is enabled through a pH swing by a pyridine-substituted diiminoguanidine (PyDIG) photobase. Upon irradiation with UV light, the PyDIG photobase undergoes photoisomerization from the E,E to the Z,Z isomer, corresponding to a pK a increase of 2.8 units that activates GlyGly for DAC through deprotonation. After the GlyGly/PyDIG solvent is saturated with atmospheric carbon dioxide, leaving it in the dark under ambient conditions leads to the isomerization of PyDIG from the Z,Z back to the E,E isomer, which is accompanied by a pH drop and CO 2 release. To demonstrate the recyclability of the GlyGly/PyDIG solvent, we have completed six consecutive DAC cycles, with a measured average cyclic capacity in the range of 0.21–0.26 mol CO 2 per mol of GlyGly/PyDIG. These results open the prospect for energy-efficient DAC cycles completed entirely at ambient conditions, thereby avoiding the significant energy penalties associated with heating and boiling aqueous solvents.

Einkauf, Jeffrey D. [Oak Ridge National Laboratory↗
DOE OSTI2019

Room Temperature Methane Capture and Activation by Ni Clusters Supported on TiC(001): Effects of Metal–Carbide Interactions on the Cleavage of the C–H Bond

Methane is an extremely stable molecule, a major component of natural gas, and also one of the most potent greenhouse gases contributing to global warming. Consequently, the capture and activation of methane is a challenging and intensively studied topic. A major research goal is to find systems that can activate methane, even at low temperatures. In this work, combining ultrahigh vacuum catalytic experiments, X-ray photoemission spectra, and accurate density functional theory (DFT) based calculations, we show that small Ni clusters dispersed on the (001) surface of TiC are able to capture and dissociate methane at room temperature. Our DFT calculations reveal that two-dimensional Ni clusters are responsible for this chemical transformation, confirming that the lability of the supported clusters appears to be a critical aspect in the strong adsorption of methane. A small energy barrier of 0.18 eV is predicted for CH 4 dissociation into adsorbed methyl and atomic hydrogen species. In addition, the calculated reaction free energy profile at 300 K and 1 atm of CH 4 shows no effective energy barriers in the system. Comparison with other reported systems which activate methane at room temperature, including oxide and zeolite-based materials, indicates that a different chemistry takes place on our metal/carbide system. Lastly, the discovery of a carbide-based surface able to activate methane at low temperatures paves the road for the design of new types of catalysts which can efficiently convert this hydrocarbon into other added-value chemicals, with implications in climate change mitigation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Anion-Functionalized Task-Specific Ionic Liquids: Molecular Origin of Change in Viscosity upon CO 2 Capture

The structure and dynamics of a task-specific ionic liquid (TSIL), trihexyl(tetradecyl)phosphonium imidazolate, before and after absorbing CO 2 were studied with a molecular dynamics (MD) simulation. This particular ionic liquid is one of several newly discovered azole-based TSILs for equimolar CO 2 capture. Unlike other TSILs whose viscosity increases drastically upon reaction with CO 2 , its viscosity decreases after CO 2 absorption. This unique behavior was confirmed in our MD simulation. In this study, we find that after CO 2 absorption the translational dynamics of the whole system is accelerated, accompanied by an accelerated rotational dynamics of the cations. Radial distribution function and spatial distribution function analyses show that the anions become asymmetric after reaction with CO 2 , and this causes the imbalance of the interaction between the positive and negative regions of the ions. The interaction between the phosphorus atom of the cation and oxygen atoms of the carboxyl group on the anion is enhanced, while that between the phosphorus atom and the naked nitrogen atom of the anion is weakened. The ion-pair correlation functions further support that the weakened interaction leads to faster dissociation of cation–anion pairs, thereby causing an accelerated dynamics. Hence, the asymmetry of anions influences the dynamics of the system and affects the viscosity. In conclusion, this insight may help design better TSILs with decreased viscosity for CO 2 capture.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Capturing the genetic makeup of the active microbiome in situ

More than any other technology, nucleic acid sequencing has enabled microbial ecology studies to be complemented with the data volumes necessary to capture the extent of microbial diversity and dynamics in a wide range of environments. In order to truly understand and predict environmental processes, however, the distinction between active, inactive and dead microbial cells is critical. Also, experimental designs need to be sensitive toward varying population complexity and activity, and temporal as well as spatial scales of process rates. There are a number of approaches, including single-cell techniques, which were designed to study in situ microbial activity and that have been successively coupled to nucleic acid sequencing. The exciting new discoveries regarding in situ microbial activity provide evidence that future microbial ecology studies will indispensably rely on techniques that specifically capture members of the microbiome active in the environment. Herein, we review those currently used activity-based approaches that can be directly linked to shotgun nucleic acid sequencing, evaluate their relevance to ecology studies, and discuss future directions.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2017

Capture of heavy hydrogen isotopes in a metal-organic framework with active Cu(I) sites

The production of pure deuterium and the removal of tritium from nuclear waste are the key challenges in separation of light isotopes. Presently, the technological methods are extremely energy- and cost-intensive. Here we report the capture of heavy hydrogen isotopes from hydrogen gas by selective adsorption at Cu(I) sites in a metal-organic framework. At the strongly binding Cu(I) sites (32 kJ mol -1 ) nuclear quantum effects result in higher adsorption enthalpies of heavier isotopes. The capture mechanism takes place most efficiently at temperatures above 80 K, when an isotope exchange allows the preferential adsorption of heavy isotopologues from the gas phase. Large difference in adsorption enthalpy of 2.5 kJ mol -1 between D 2 and H 2 results in D 2 -over-H 2 selectivity of 11 at 100 K, to the best of our knowledge the largest value known to date. Combination of thermal desorption spectroscopy, Raman measurements, inelastic neutron scattering and first principles calculations for H 2 /D 2 mixtures allows the prediction of selectivities for tritium-containing isotopologues.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

A net-zero emissions strategy for China’s power sector using carbon-capture utilization and storage

Decarbonized power systems are critical to mitigate climate change, yet methods to achieve a reliable and resilient near-zero power system are still under exploration. This study develops an hourly power system simulation model considering high-resolution geological constraints for carbon-capture-utilization-and-storage to explore the optimal solution for a reliable and resilient near-zero power system. This is applied to 31 provinces in China by simulating 10,450 scenarios combining different electricity storage durations and interprovincial transmission capacities, with various shares of abated fossil power with carbon-capture-utilization-and-storage. Here, we show that allowing up to 20% abated fossil fuel power generation in the power system could reduce the national total power shortage rate by up to 9.0 percentages in 2050 compared with a zero fossil fuel system. A lowest-cost scenario with 16% abated fossil fuel power generation in the system even causes 2.5% lower investment costs in the network (or $16.8 billion), and also increases system resilience by reducing power shortage during extreme climatic events.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2025

Mesh-like structure integrated core-shell-shell nanocomposites for enhanced stability and performance in carbon capture

Carbon capture is essential for mitigating climate change, yet most sorbents struggle to combine high capacity with chemical stability. Here we report core-shell-shell (CSS) nanocomposites that integrate adsorption efficiency with exceptional robustness. The design couples a metal-organic framework (MOF) core, which enriches local CO 2 concentration, with a polyamine shell that is reorganized into a porous, ordered network through entanglement with an outer covalent organic framework (COF) shell. This hierarchical architecture enables dual amine functionalization via sequential “click” and Schiff-base reactions, achieving a CO 2 uptake of 3.4 mmol g −1 at 1 bar. The COF outer layer also acts as a protective barrier, suppressing humidity interference and doubling cycling stability under simulated flue gas. Remarkably, the nanocomposites maintain structural integrity after one week in strongly acidic (3 M HNO 3 ) or basic (NaOH, pH=14) environments, underscoring their chemical resilience. By uniting high capacity, cycling durability, and environmental tolerance, this CSS strategy offers a versatile platform for next-generation carbon capture materials.

Yang, Sizhuo [Lawrence Berkeley National Laborator↗
DOE OSTI2026

Capture, storage, and re-use of liquid hydrogen boil-off for aviation and aerospace applications

Despite major interest in the use of liquid hydrogen as a fuel for aviation and aerospace sectors, loss of hydrogen through boil-off continues to be a hurdle as it causes financial loss, indirect greenhouse gas emissions, and safety concerns. Herein, we perform techno-economic analysis, calibrated with experimental measurements, to assess the use of sorbents to capture and condition hydrogen boil-off events in the range of 1.5 to 70 tonnes per day at launch sites and airports. We evaluate the direct delivery of captured boil-off to combustion engines and fuel cells, comparing against boil-off re-liquification and compression. Results indicate probable cost-effectiveness at delivered liquid hydrogen prices above 0.9 U.S. dollar ($) per kg H2 at airports, and above 10 $ per kg H2 at launch sites where 10% or more of hydrogen is lost to boil-off.

08 HYDROGEN↗
DOE OSTI2019

Capture of nitrogen dioxide and conversion to nitric acid in a porous metal–organic framework

Air pollution by nitrogen oxides, NO x , is a major problem, and new capture and abatement technologies are urgently required. Here, we report a metal-organic framework (Manchester Framework Material 520 (MFM-520)) that can efficiently confine dimers of NO 2 , which results in a high adsorption capacity of 4.2 mmol g -1 (298 K, 0.01 bar) with full reversibility and no loss of capacity over 125 cycles. Treatment of NO 2 @MFM-520 with water in air leads to a quantitative conversion of the captured NO 2 into HNO 3 , an important feedstock for fertilizer production, and fully regenerates MFM-520. Here, the confinement of N 2 O 4 inside nanopores was established at a molecular level, and the dynamic breakthrough experiments using both dry and humid NO 2 gas streams verify the excellent stability and selectivity of MFM-520 and confirm its potential for precious-metal-free deNO x technologies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Direct air capture of CO 2 via aqueous-phase absorption and crystalline-phase release using concentrated solar power

Using negative emissions technologies for the net removal of greenhouse gases from the atmosphere could provide a pathway to limit global temperature rises. Direct air capture of carbon dioxide offers the prospect of permanently lowering the atmospheric CO 2 concentration, providing that economical and energy-efficient technologies can be developed and deployed on a large scale. Here in this paper, we report an approach to direct air capture, at the laboratory scale, using mostly off-the-shelf materials and equipment. First, CO 2 absorption is achieved with readily available and environmentally friendly aqueous amino acid solutions (glycine and sarcosine) using a household humidifier. The CO 2 -loaded solutions are then reacted with a simple guanidine compound, which crystallizes as a very insoluble carbonate salt and regenerates the amino acid sorbent. Finally, effective CO 2 release and near-quantitative regeneration of the guanidine compound are achieved by relatively mild heating of the carbonate crystals using concentrated solar power.

14 SOLAR ENERGY↗
DOE OSTI2018

Affinity-based capture and identification of protein effectors of the growth regulator ppGpp

The nucleotide ppGpp is a highly conserved regulatory molecule in bacteria that helps tune growth rate to nutrient availability. Despite decades of study, how ppGpp regulates growth remains poorly understood. Here, we developed and validated a capture-compound mass spectrometry approach that identified >50 putative ppGpp targets in Escherichia coli. These targets control many key cellular processes and include 13 enzymes required for nucleotide synthesis. We demonstrated that ppGpp inhibits the de novo synthesis of all purine nucleotides by directly targeting the enzyme PurF. By solving a structure of PurF bound to ppGpp, we designed a mutation that ablates ppGpp-based regulation, leading to dysregulation of purine-nucleotide synthesis following ppGpp accumulation. Collectively, our results provide new insights into ppGpp-based growth control and a nearly comprehensive set of targets for future exploration. Furthermore, the capture compounds developed should also enable the rapid identification of ppGpp targets in any species, including pathogens.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

TiO(OH) 2 – highly effective catalysts for optimizing CO 2 desorption kinetics reducing CO 2 capture cost: A new pathway

The objective is to find a new pathway for significant reduction in CO 2 capture energy consumption. Specifically, nanoporous TiO(OH) 2 was used to realize the objective, which was desired as a catalyst to significantly accelerate the decomposition of aqueous NaHCO3, essentially CO 2 desorption – the key step of Na2CO 3 /NaHCO 3 based CO 2 capture technologies from overall CO 2 energy consumption perspective. Effects of several important factors on TiO(OH) 2 -catalyzed NaHCO3 decomposition were investigated. The quantity of CO 2 generated from 0.238mol/L NaHCO 3 at 65°C with catalyst is ~800% of that generated without the presence of catalyst. When a 12W vacuum pump was used for carrying the generated CO 2 out of reactor, the total amount of CO 2 released was improved by ~2,500% under the given experimental conditions. No significant decrease in the catalytic effect of TiO(OH) 2 was observed after five cyclic CO 2 activated tests. In addition, characterizations with in-situ Fourier transform infrared spectroscopy, thermal gravity analysis and Brunauer-Emmett-Teller of TiO(OH) 2 indicate that TiO(OH) 2 is quite stable. The discovery in this research could inspire scientists’ interests in starting to focus on a new pathway instead of making huge effort or investment in designing high-capacity but expensive CO 2 sorbent for developing practical or cost-effective CO 2 technologies.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Capturing convection essential for projections of climate change in African dust emission

The summertime Sahara and Sahel are the world’s largest source of airborne mineral dust. Cold-pool outflows from moist convection (‘haboobs’) are a dominant source of summertime uplift but are essentially missing in global models, raising major questions on the reliability of climate projections of dust and dust impacts. Here we use convection-permitting simulations of pan-African climate change, which explicitly capture haboobs, to investigate whether this key limitation of global models affects projections. We show that explicit convection is key to capturing the observed summertime maximum of dust-generating winds, which is missed with parameterised convection. Despite this, future climate changes in dust-generating winds are more sensitive to the effects of explicit convection on the wider meteorology than they are to the haboobs themselves, with model differences in the change in dust-generating winds reaching 60% of current values. The results therefore show the importance of improving convection in climate models for dust projections.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Harnessing interfaces for direct air capture

Here, atmospheric CO 2 removal through direct air capture (DAC) may help restore CO 2 concentrations to optimal levels, but slow CO 2 uptake rates remain a major impediment. Now, an intensified DAC process has been demonstrated, involving enhanced CO 2 capture rates and reactive K 2 CO 3 crystallization at the interface of ultraconcentrated KOH solutions with air.

Custelcean, Radu [Oak Ridge National Laboratory (O↗
DOE OSTI2016

Capturing relativistic wakefield structures in plasmas using ultrashort high-energy electrons as a probe

A new method capable of capturing coherent electric field structures propagating at nearly the speed of light in plasma with a time resolution as small as a few femtoseconds is proposed. This method uses a few femtoseconds long relativistic electron bunch to probe the wake produced in a plasma by an intense laser pulse or an ultra-short relativistic charged particle beam. As the probe bunch traverses the wake, its momentum is modulated by the electric field of the wake, leading to a density variation of the probe after free-space propagation. This variation of probe density produces a snapshot of the wake that can directly give many useful information of the wake structure and its evolution. Furthermore, this snapshot allows detailed mapping of the longitudinal and transverse components of the wakefield. We develop a theoretical model for field reconstruction and verify it using 3-dimensional particle-in-cell (PIC) simulations. This model can accurately reconstruct the wakefield structure in the linear regime, and it can also qualitatively map the major features of nonlinear wakes. As a result, the capturing of the injection in a nonlinear wake is demonstrated through 3D PIC simulations as an example of the application of this new method.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Spatially-Resolved Proteomics: Rapid Quantitative Analysis of Laser Capture Microdissected Alveolar Tissue Samples

Global proteomics approaches allow characterization of whole tissue lysates to an impressive depth. However, it is now increasingly recognized that to better understand the complexity of multicellular organisms, global protein profiling of specific spatially defined regions/substructures of tissues (i.e. spatially-resolved proteomics) is essential. Laser capture microdissection (LCM) enables microscopic isolation of defined regions of tissues preserving crucial spatial information. However, current proteomics workflows entail several manual sample preparation steps and are challenged by the microscopic mass-limited samples generated by LCM, and that impact measurement robustness, quantification, and throughput. Here, we coupled LCM with a fully automated sample preparation workflow that with a single manual step allows: protein extraction, tryptic digestion, peptide cleanup and LC-MS/MS analysis of proteomes from microdissected tissues. Benchmarking against the current state of the art in ultrasensitive global proteomic analysis, our approach demonstrated significant improvements in quantification and throughput. Using our LCM-SNaPP proteomics approach, we characterized to a depth of more than 3,400 proteins, the ontogeny of protein changes during normal lung development in laser capture microdissected alveolar tissue containing ~4,000 cells per sample. Importantly, the data revealed quantitative changes for 350 low abundance transcription factors and signaling molecules, confirming earlier transcript-level observations and defining seven modules of coordinated transcription factor/signaling molecule expression patterns, suggesting that a complex network of temporal regulatory control directs normal lung development with epigenetic regulation fine-tuning pre-natal developmental processes. Furthermore, our LCM-proteomics approach facilitates efficient, spatially-resolved, ultrasensitive global proteomics analyses in high-throughput that will be enabling for several clinical and biological applications.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2013

Structural and electronic properties of Li8ZrO6 and its CO2 capture capabilities: an ab initio thermodynamic approach

The structural, electronic, and phonon properties of Li8ZrO6 are investigated with the application of density functional theory and lattice phonon dynamics. Based on the calculated data, the thermodynamics of CO2 absorption?desorption for Li8ZrO6 is analyzed and compared with those of Li2ZrO3 and Li6Zr2O7. The band gap of Li8ZrO6 is indirect along G?L with a value of 4.74 eV. From the calculated thermodynamic properties of Li8ZrO6 reacting with CO2, we found that Li8ZrO6 could be regenerated at high temperatures (>1100 K). Our results indicated that the lithium zirconate with a lower Li2O/ZrO2 ratio has a lower turnover temperature. Hence, by mixing or doping two or more materials to form a new material, it is possible to find or synthesize CO2 sorbents that can fit the industrial needs for optimal performance. Although the CO2 capture capacity of Li8ZrO6 is much higher than that of Li2ZrO3, the high energy required for regeneration, the capacity loss during long absorption?desorption cycles, solid sintering at high temperature, and the material cost may affect its overall capture performance. Our results also provided some general guidelines for designing new CO2 sorbents.

Duan, Y↗