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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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31 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Dynamic Effects and Hydrogen Bonding in Mixed-Halide Perovskite Solar Cell Absorbers

The organic component (methylammonium) of CH 3 NH 3 PbI 3- x Cl x -based perovskites shows electronic hybridization with the inorganic framework via H-bonding between N and I sites. Femtosecond dynamics induced by core excitation are shown to strongly influence the measured X-ray emission spectra and the resonant inelastic soft X-ray scattering of the organic components. The N K core excitation leads to a greatly increased N-H bond length that modifies and strengthens the interaction with the inorganic framework compared to that in the ground state. The study indicates that excited-state dynamics must be accounted for in spectroscopic studies of this perovskite solar cell material, and the organic-inorganic hybridization interaction suggests new avenues for probing the electronic structure of this class of materials. Furthermore, it is incidentally shown that beam damage to the methylamine component can be avoided by moving the sample under the soft X-ray beam to minimize exposure and that this procedure is necessary to prevent the creation of experimental artifacts.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Ambient Pressure XPS Investigation of Thermally Stable Halide Perovskite Solar Cells via Post-Treatment

Long-term thermal stability is one limiting factor that impedes the commercialization of perovskite solar cell. Inspired by our prior results from machine learning, we discover that coating a thin layer of 4,4’-dibromotriphenylamine (DBTPA) on top of a CH 3 NH 3 PbI 3 (MAPbI 3 ) thin film can improve the stability of the resultant perovskite solar cells. The passivated perovskite solar cells retained more than 96% of their initial power conversion efficiency over 1000 h at 85 °C in N2 atmosphere without encapsulation. Near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) was employed to investigate the evolution of composition and evaluate thermal and moisture stability by in-situ studies. A comparison between pristine MAPbI 3 films and DBTPA-treated films shows the DBTPA treatment suppresses the escape of iodide and methylamine up to 150 °C under 5 mbar humidity. Furthermore, we have used ATR-FTIR and XPS to probe the interactions between DBTPA and MAPbI3 surface. The results prove that DBTPA coordinate with perovskite by Lewis acid-base and cation-π interaction. Compared with the 19.9% efficiency of pristine sample, the champion efficiency of passivated sample reaches 20.6%. Finally, our results reveal DBTPA as a new post-treating molecule that not only leads to the improvement of photovoltaic efficiency but also thermal and moisture stability.

14 SOLAR ENERGY↗
DOE OSTI2021

Large-scale protein level comparison of Deltaproteobacteria reveals cohesive metabolic groups

Abstract Deltaproteobacteria, now proposed to be the phyla Desulfobacterota, Myxococcota, and SAR324, are ubiquitous in marine environments and play essential roles in global carbon, sulfur, and nutrient cycling. Despite their importance, our understanding of these bacteria is biased towards cultured organisms. Here we address this gap by compiling a genomic catalog of 1 792 genomes, including 402 newly reconstructed and characterized metagenome-assembled genomes (MAGs) from coastal and deep-sea sediments. Phylogenomic analyses reveal that many of these novel MAGs are uncultured representatives of Myxococcota and Desulfobacterota that are understudied. To better characterize Deltaproteobacteria diversity, metabolism, and ecology, we clustered ~1 500 genomes based on the presence/absence patterns of their protein families. Protein content analysis coupled with large-scale metabolic reconstructions separates eight genomic clusters of Deltaproteobacteria with unique metabolic profiles. While these eight clusters largely correspond to phylogeny, there are exceptions where more distantly related organisms appear to have similar ecological roles and closely related organisms have distinct protein content. Our analyses have identified previously unrecognized roles in the cycling of methylamines and denitrification among uncultured Deltaproteobacteria. This new view of Deltaproteobacteria diversity expands our understanding of these dominant bacteria and highlights metabolic abilities across diverse taxa.

Langwig, Marguerite V. (ORCID:0000000202472816)↗
DOE OSTI2023

Insights into pyrrolysine function from structures of a trimethylamine methyltransferase and its corrinoid protein complex

The 22nd genetically encoded amino acid, pyrrolysine, plays a unique role in the key step in the growth of methanogens on mono-, di-, and tri-methylamines by activating the methyl group of these substrates for transfer to a corrinoid cofactor. Previous crystal structures of the Methanosarcina barkeri monomethylamine methyltransferase elucidated the structure of pyrrolysine and provide insight into its role in monomethylamine activation. Herein, we report the second structure of a pyrrolysine-containing protein, the M. barkeri trimethylamine methyltransferase MttB, and its structure bound to sulfite, a substrate analog of trimethylamine. We also report the structure of MttB in complex with its cognate corrinoid protein MttC, which specifically receives the methyl group from the pyrrolysine-activated trimethylamine substrate during methanogenesis. Together these structures provide key insights into the role of pyrrolysine in methyl group transfer from trimethylamine to the corrinoid cofactor in MttC.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Microbial functional diversity across biogeochemical provinces in the central Pacific Ocean

Enzymes catalyze key reactions within Earth’s life-sustaining biogeochemical cycles. Here, we use metaproteomics to examine the enzymatic capabilities of the microbial community (0.2 to 3 µm) along a 5,000-km-long, 1-km-deep transect in the central Pacific Ocean. Eighty-five percent of total protein abundance was of bacterial origin, with Archaea contributing 1.6%. Over 2,000 functional KEGG Ontology (KO) groups were identified, yet only 25 KO groups contributed over half of the protein abundance, simultaneously indicating abundant key functions and a long tail of diverse functions. Vertical attenuation of individual proteins displayed stratification of nutrient transport, carbon utilization, and environmental stress. The microbial community also varied along horizontal scales, shaped by environmental features specific to the oligotrophic North Pacific Subtropical Gyre, the oxygen-depleted Eastern Tropical North Pacific, and nutrient-rich equatorial upwelling. Some of the most abundant proteins were associated with nitrification and C1 metabolisms, with observed interactions between these pathways. The oxidoreductases nitrite oxidoreductase (NxrAB), nitrite reductase (NirK), ammonia monooxygenase (AmoABC), manganese oxidase (MnxG), formate dehydrogenase (FdoGH and FDH), and carbon monoxide dehydrogenase (CoxLM) displayed distributions indicative of biogeochemical status such as oxidative or nutritional stress, with the potential to be more sensitive than chemical sensors. Enzymes that mediate transformations of atmospheric gases like CO, CO 2 , NO, methanethiol, and methylamines were most abundant in the upwelling region. Here, we identified hot spots of biochemical transformation in the central Pacific Ocean, highlighted previously understudied metabolic pathways in the environment, and provided rich empirical data for biogeochemical models critical for forecasting ecosystem response to climate change.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Methylotrophy in the Mire: direct and indirect routes for methane production in thawing permafrost

While wetlands are major sources of biogenic methane (CH 4 ), our understanding of resident microbial metabolism is incomplete, which compromises the prediction of CH 4 emissions under ongoing climate change. Here, we employed genome-resolved multi-omics to expand our understanding of methanogenesis in the thawing permafrost peatland of Stordalen Mire in Arctic Sweden. In quadrupling the genomic representation of the site’s methanogens and examining their encoded metabolism, we revealed that nearly 20% of the metagenome-assembled genomes (MAGs) encoded the potential for methylotrophic methanogenesis. Further, 27% of the transcriptionally active methanogens expressed methylotrophic genes; for Methanosarcinales and Methanobacteriales MAGs, these data indicated the use of methylated oxygen compounds (e.g., methanol), while for Methanomassiliicoccales, they primarily implicated methyl sulfides and methylamines. In addition to methanogenic methylotrophy, >1,700 bacterial MAGs across 19 phyla encoded anaerobic methylotrophic potential, with expression across 12 phyla. Metabolomic analyses revealed the presence of diverse methylated compounds in the Mire, including some known methylotrophic substrates. Active methylotrophy was observed across all stages of a permafrost thaw gradient in Stordalen, with the most frozen non-methanogenic palsa found to host bacterial methylotrophy and the partially thawed bog and fully thawed fen seen to house both methanogenic and bacterial methylotrophic activities. Methanogenesis across increasing permafrost thaw is thus revised from the sole dominance of hydrogenotrophic production and the appearance of acetoclastic at full thaw to consider the co-occurrence of methylotrophy throughout. Collectively, these findings indicate that methanogenic and bacterial methylotrophy may be an important and previously underappreciated component of carbon cycling and emissions in these rapidly changing wetland habitats.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on H7C(NO)3 by Materials Project

CH3NH2NH2NO3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four ammonia molecules, four methylamine molecules, and four nitric acid molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H8C3N2O by Materials Project

(CNH4)2CO crystallizes in the orthorhombic Fdd2 space group. The structure is zero-dimensional and consists of eight formaldehyde molecules and sixteen methylamine molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SbH3CS2N by Materials Project

CNH2SbHS2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of four methylamine molecules and one SbHS2 ribbon oriented in the (1, 0, 1) direction. In the SbHS2 ribbon, there are two inequivalent Sb3+ sites. In the first Sb3+ site, Sb3+ is bonded in a distorted rectangular see-saw-like geometry to four S2- atoms. There are a spread of Sb–S bond distances ranging from 2.44–3.19 Å. In the second Sb3+ site, Sb3+ is bonded in a distorted rectangular see-saw-like geometry to four S2- atoms. There are a spread of Sb–S bond distances ranging from 2.45–3.11 Å. There are two inequivalent H+0.33+ sites. In the first H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one S2- atom. The H–S bond length is 1.35 Å. In the second H+0.33+ site, H+0.33+ is bonded in a single-bond geometry to one S2- atom. The H–S bond length is 1.35 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted single-bond geometry to two equivalent Sb3+ and one H+0.33+ atom. In the second S2- site, S2- is bonded in an L-shaped geometry to two Sb3+ atoms. In the third S2- site, S2- is bonded in an L-shaped geometry to two Sb3+ atoms. In the fourth S2- site, S2- is bonded in a distorted single-bond geometry to two equivalent Sb3+ and one H+0.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BH5C4(N2O)2 by Materials Project

(B)6(CN)4(H5(C2N)2)2(CNH2)4(CHNO2)4(N2H)4(H(CO)2)2H2 crystallizes in the orthorhombic Pnn2 space group. The structure is zero-dimensional and consists of six boron molecules; four carbamic acid molecules; four diazene molecules; two formalin formaldehyde molecules; two hydrogen molecules; four hydrogen cyanide molecules; four methylamine molecules; and two n,n'-dimethylethylenediamine molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrH9(CN2)3 by Materials Project

CrC2N3H4CNH3N2H2 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of two hydrogen molecules; two methylamine molecules; two nitrogen molecules; and one CrC2N3H4 ribbon oriented in the (1, 0, 0) direction. In the CrC2N3H4 ribbon, there are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded in a distorted hexagonal bipyramidal geometry to two equivalent C2+, four N3-, and two equivalent H1+ atoms. Both Cr–C bond lengths are 2.01 Å. There are two shorter (2.16 Å) and two longer (2.18 Å) Cr–N bond lengths. Both Cr–H bond lengths are 1.81 Å. In the second Cr3+ site, Cr3+ is bonded in a distorted square co-planar geometry to two equivalent N3- and two equivalent H1+ atoms. Both Cr–N bond lengths are 1.87 Å. Both Cr–H bond lengths are 1.84 Å. There are two inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a distorted single-bond geometry to one Cr3+ and one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a tetrahedral geometry to one N3- and three H1+ atoms. The C–N bond length is 1.41 Å. All C–H bond lengths are 1.10 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted T-shaped geometry to two Cr3+ and one N3- atom. The N–N bond length is 1.19 Å. In the second N3- site, N3- is bonded in a 2-coordinate geometry to one Cr3+ and one N3- atom. In the third N3- site, N3- is bonded in a linear geometry to two C2+ atoms. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a water-like geometry to two Cr3+ atoms. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H8C3N2O by Materials Project

(CNH4)2CO crystallizes in the orthorhombic Fdd2 space group. The structure is zero-dimensional and consists of eight formaldehyde molecules and sixteen methylamine molecules.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Gas-Phase Oxidation Mechanisms of Nitrogen-Containing Organic Compounds

Nitrogen-containing organic molecules play essential roles in nearly every aspect of chemistry. The importance of these species within gas-phase chemistry has increased in recent years, due to their emissions from wildfires, crude biofuels, ammonia combustion, and CO 2 capture facilities. However, there is a lack of detailed relevant mechanistic and kinetic studies of N-compounds, resulting in poor representation of these pathways within chemical models. In this report, we detail our exploration of the gas-phase oxidation mechanisms of pyrrole, imidazole, pyrrolidine, methylamine, and dimethylamine, done by employing multiplexed VUV photoionization mass spectrometry coupled with KinBot, a computational tool that automatically explores multi-well potential energy surfaces. Overall, we vastly expanded the known gas-phase oxidation mechanisms and chemical kinetics of these species. This work will improve the accuracy and completeness of atmospheric and combustion chemistry models, ultimately leading to better-informed decision-makers in the energy and environmental sectors.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗