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DOE OSTI2020

Materials Data on Co(HO)2 by Materials Project

Co(OH)2 crystallizes in the triclinic P1 space group. The structure is two-dimensional and consists of one Co(OH)2 sheet oriented in the (0, 0, 1) direction. Co2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Co–O bond distances ranging from 2.04–2.12 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Co2+ and one H1+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Co2+ and one H1+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Co(HO)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Co(HO)2 by Materials Project

36 MATERIALS SCIENCE↗

DOE OSTI2025

Active Sites in the Dealuminated Beta Zeolite-Supported Cobalt Catalyst for Non-Oxidative Ethane Dehydrogenation

Dispersed metal species in siliceous zeolites have been actively studied for non-oxidative dehydrogenation of ethane (NDE). Fundamental insights into the dynamics of metal species in zeolites under reaction conditions have rarely been explored. Herein, we report an atomic level understanding of the dynamics and activity of cobalt (Co) sites in dealuminated Beta zeolite (DeAl-BEA) for NDE during induction and reaction conditions with extensive characterization techniques such as diffuse reflectance UV–vis, solid state nuclear magnetic resonance and X-ray photoelectron, X-ray diffraction along with in situ Fourier transform infrared and X-ray absorption spectroscopy. For a catalyst with 0.5 mass % Co loading, tetrahedral Co 2+ mononuclear sites, di-coordinated to the zeolite framework and with two silanol groups in vicinity (i.e., (≡SiO) 2 Co(HO–Si≡) 2 ), form upon exposure to hydrogen during induction and persist through the NDE reaction. Increasing the Co loading to 3.0 mass % yielded Co sites with similar electronic and coordination structures but slightly elongated Co–O bonds. Upon cooling to room temperature, the Co sites persisted in the same coordination environment, though the disappearance of a feature in the Co K-edge near-edge region revealed changes in the active site’s electronic structure coinciding with modest shifts in bond lengths. The electronic structure and activity of (≡SiO) 2 Co(HO–Si≡) 2 sites were studied comparatively to a few other hypothetical Co 2+ coordination structures, using electronic structure calculations and microkinetic simulations. The simulations showed that NDE is controlled by β-hydride elimination following C–H bond activation and that Co-sites possessing flexibility because of neighboring silanol defects are more active. Interestingly, dinuclear Co–O–Co sites (i.e., (≡SiO)Co(HO–Si≡) 2 –O–(HO–Si≡) 2 Co(≡SiO)) were more active than the mononuclear (≡SiO) 2 Co(HO–Si≡) 2 sites because of favorable hydrogen bonding with the vicinal silanol groups. In conclusion, the present study bridges the gap between the knowledge acquired by ex-situ characterizations and the active sites under the reaction conditions in alkane dehydrogenation chemistry.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Kinetics and selectivity of methane oxidation on an IrO 2 (110) film

Undercoordinated, bridging O-atoms (O br ) are highly active as H-acceptors in alkane dehydrogenation on IrO 2 (110) surfaces but transform to HO br groups that are inactive toward hydrocarbons. The low C–H activity and high stability of the HO br groups cause the kinetics and product selectivity during CH 4 oxidation on IrO 2 (110) to depend sensitively on the availability of O br atoms prior to the onset of product desorption. From temperature programmed reaction spectroscopy (TPRS) and kinetic simulations, we identified two O br -coverage regimes that distinguish the kinetics and product formation during CH 4 oxidation on IrO 2 (110). Under excess O br conditions, when the initial O br coverage is greater than that needed to oxidize all the CH 4 to CO 2 and HO br groups, complete CH 4 oxidation is dominant and produces CO 2 in a single TPRS peak between 450 and 500 K. However, under O br -limited conditions, nearly all the initial O br atoms are deactivated by conversion to HO br or abstracted after only a fraction of the initially adsorbed CH 4 oxidizes to CO 2 and CO below 500 K. Thereafter, some of the excess CH x groups abstract H and desorb as CH 4 above ~500 K while the remainder oxidize to CO 2 and CO at a rate that is controlled by the rate at which Obr atoms are regenerated from HObr during the formation of CH 4 and H 2 O products. We also show that chemisorbed O-atoms ('on-top O') on IrO 2 (110) enhance CO 2 production below 500 K by efficiently abstracting H from Obr atoms and thereby increasing the coverage of O br atoms available to completely oxidize CH x groups at low temperature. Furthermore, our results provide new insights for understanding factors which govern the kinetics and selectivity during CH 4 oxidation on IrO 2 (110) surfaces.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2020

Materials Data on Ho2Co17 by Materials Project

Ho2Co17 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 12-coordinate geometry to eighteen Co atoms. There are a spread of Ho–Co bond distances ranging from 2.93–3.25 Å. In the second Ho site, Ho is bonded in a 2-coordinate geometry to twenty Co atoms. There are a spread of Ho–Co bond distances ranging from 2.88–3.13 Å. There are four inequivalent Co sites. In the first Co site, Co is bonded in a 2-coordinate geometry to one Ho and thirteen Co atoms. There are a spread of Co–Co bond distances ranging from 2.32–2.67 Å. In the second Co site, Co is bonded to two equivalent Ho and ten Co atoms to form CoHo2Co10 cuboctahedra that share corners with fourteen CoHo2Co10 cuboctahedra, edges with six equivalent CoHo3Co9 cuboctahedra, and faces with ten CoHo2Co10 cuboctahedra. There are four shorter (2.39 Å) and four longer (2.40 Å) Co–Co bond lengths. In the third Co site, Co is bonded in a 12-coordinate geometry to two Ho and ten Co atoms. There are a spread of Co–Co bond distances ranging from 2.34–2.54 Å. In the fourth Co site, Co is bonded to three Ho and nine Co atoms to form a mixture of distorted face, edge, and corner-sharing CoHo3Co9 cuboctahedra. Both Co–Co bond lengths are 2.41 Å.

36 MATERIALS SCIENCE↗

NASA NTRS1988

Airborne Doppler lidar detection of wind shear. Results of performance analysis

Results of a performance analysis of an airborne Doppler radar wind shear detection system are given in vugraph form. It was concluded that both CO sub 2 and Ho:YAG lasers are feasible for dry microburst applications, but with limited performance in wet microbursts. The Ho:YAG performs better than the CO sub 2 for a set of identical lidar parameters.

Huffaker, R. Milton↗

NASA NTRS1994

(abstract) Odd Hydrogen in the Atmospheres of Earth and Mars

The Martian atmosphere has many features in common with the terrestrial mesosphere. Both share similar pressure and temperature ranges, and much of the same chemistry operates in each. For example, the radical species H, OH, and H(sub 2)O, which comprise the odd hydrogen family, are of central importance in the catalytic destruction of CO and O(sub 3) in both atmospheres. The inclusion of recent chemical kinetics data, specifically temperature dependent CO(sub 2) absorption cross-sections, into our one dimensional photochemical model of the Martial atmosphere shows that oxidation of CO by odd hydrogen is too efficient. The incorporation of smaller cross sections for CO(sub 2) leads to an enhanced photolysis rate of water vapor, increasing odd hydrogen to the point where the predicted mixing ratio of CO in our model is substantially less than the observed value of 6.5 x 10(sup -4). Interestingly, most photochemical models of the terrestrial mesosphere underestimate the CO and O(sub 3) densities using currently accepted photodissociation and kinetic rate coefficients. This has also been attributed to an overabundance of odd hydrogen in the models. We shall show that agreement between models and observations of CO in the Martian atmosphere as well as of CO and O(sub 3) in the terrestrial mesosphere can be achieved by revising the rate constants for the reactions OH + HO(sub 2) and CO + OH within their published uncertainties. The fact that similar revisions alleviate discrepancies in both the terrestrial and Martian atmospheres warrants a re-evaluation of these key rate constants at the appropriate temperatures and pressures.

dioxide ozone odd hydrogen family pressure tempera↗

DOE OSTI2020

Fast Advective Water Flow through Nanochannels in Clay Interlayers: Implications for Moisture Transport in Soils and Unconventional Oil/Gas Production

Water flow in nanometer or sub-nanometer hydrophilic channels bears special importance in diverse fields of science and engineering. However, the nature of such water flow remains elusive. In this work, we report our molecular-modeling results on water flow in a sub-nanometer clay interlayer between two montmorillonite layers. We show that a fast advective flow can be induced by evaporation at one end of the interlayer channel, that is, a large suction pressure created by evaporation (~818 MPa) is able to drive the fast water flow through the channel (~0.88 m/s for a 46 Å-long channel). Scaled up for the pressure gradient to a 2 μm particle, the velocity of water is estimated to be about 95 μm/s, indicating that water can quickly flow through a μm-sized clay particle within seconds. The prediction seems to be confirmed by our thermogravimetric analysis of bentonite hydration and dehydration processes, which indicates that water transport at the early stage of the dehydration is a fast advective process, followed by a slow diffusion process. The possible occurrence of a fast advective water flow in clay interlayers prompts us to reassess water transport in a broad set of natural and engineered systems such as clay swelling/shrinking, moisture transport in soils, water uptake by plants, water imbibition/release in unconventional hydrocarbon reservoirs, and cap rock integrity of supercritical CO 2 storage.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1973

The hydroperoxyl radical in atmospheric chemical dynamics - Reaction with carbon monoxide.

Discussion of laboratory measurements which indicate that the reaction of the thermalized HO(2) radical with CO is exceedingly slow and that this reaction should not, therefore, be of any significance in atmospheric chemistry. The large discrepancy between the new results and data obtained earlier by Westenberg and de Haas (1972) is explained in terms of the reacting hydroperoxyl radical being in a non-Boltzmann distribution in the former study. It appears that the most important reactions of thermalized HO(2) in the atmosphere are those involving the trace gases of NO and sulfur dioxide.

Davis, D. D.↗

NASA NTRS2000

High Energy Directly Pumped Ho:YLF Laser

The most commonly used crystal architecture to produce 2 micrometer laser is co-doping Ho and Tm into a single host crystal. In this method, the stored energy transfer from the Tm (3)F4 to the Ho (5)I7 manifold is not fast enough to warrant high efficiency for short pulse applications. By separating the Ho and the Tm ions and doping the Tm in YALO3 and the Ho in YLF, we were able to directly pump the Ho (5)I7 manifold with 1.94 micrometers. The Ho:YLF laser has produced 33 mJ at 2.062 micrometers with a quantum efficiency of 0.88. The performance of each laser will be presented.

Petros, Mulugeta↗

DOE OSTI2020

Materials Data on Ho7In(CoGe3)4 by Materials Project

Ho7In(CoGe3)4 crystallizes in the tetragonal P4/m space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded in a 11-coordinate geometry to two equivalent Co, two equivalent In, and seven Ge atoms. Both Ho–Co bond lengths are 3.03 Å. Both Ho–In bond lengths are 3.32 Å. There are a spread of Ho–Ge bond distances ranging from 2.94–3.08 Å. In the second Ho site, Ho is bonded in a 8-coordinate geometry to four equivalent Co and twelve Ge atoms. All Ho–Co bond lengths are 3.14 Å. There are eight shorter (2.98 Å) and four longer (3.18 Å) Ho–Ge bond lengths. In the third Ho site, Ho is bonded in a 4-coordinate geometry to four equivalent Co and ten Ge atoms. All Ho–Co bond lengths are 3.34 Å. There are a spread of Ho–Ge bond distances ranging from 3.04–3.27 Å. Co is bonded in a 5-coordinate geometry to five Ho and five Ge atoms. There are a spread of Co–Ge bond distances ranging from 2.33–2.45 Å. In is bonded to eight equivalent Ho and four equivalent Ge atoms to form face-sharing InHo8Ge4 cuboctahedra. All In–Ge bond lengths are 2.99 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded in a 9-coordinate geometry to six Ho, one Co, one In, and one Ge atom. The Ge–Ge bond length is 2.59 Å. In the second Ge site, Ge is bonded in a 2-coordinate geometry to four Ho, two equivalent Co, and two equivalent Ge atoms. Both Ge–Ge bond lengths are 2.94 Å. In the third Ge site, Ge is bonded in a 10-coordinate geometry to five Ho, two equivalent Co, and three Ge atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho2Fe5Co12 by Materials Project

Ho2Fe5Co12 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 12-coordinate geometry to eighteen Co atoms. There are a spread of Ho–Co bond distances ranging from 2.94–3.22 Å. In the second Ho site, Ho is bonded in a 8-coordinate geometry to eight Fe and twelve Co atoms. There are two shorter (2.89 Å) and six longer (3.15 Å) Ho–Fe bond lengths. There are six shorter (3.02 Å) and six longer (3.09 Å) Ho–Co bond lengths. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded in a 2-coordinate geometry to one Ho, four Fe, and nine Co atoms. There are one shorter (2.33 Å) and three longer (2.56 Å) Fe–Fe bond lengths. There are three shorter (2.65 Å) and six longer (2.70 Å) Fe–Co bond lengths. In the second Fe site, Fe is bonded to two equivalent Ho, two equivalent Fe, and eight Co atoms to form distorted FeHo2Fe2Co8 cuboctahedra that share corners with four equivalent FeHo2Fe2Co8 cuboctahedra, corners with eighteen CoHo3Fe3Co6 cuboctahedra, edges with ten CoHo3Fe3Co6 cuboctahedra, faces with six equivalent FeHo2Fe2Co8 cuboctahedra, and faces with twelve CoHo2Fe4Co6 cuboctahedra. There are four shorter (2.41 Å) and four longer (2.44 Å) Fe–Co bond lengths. There are two inequivalent Co sites. In the first Co site, Co is bonded to two Ho, four Fe, and six Co atoms to form distorted CoHo2Fe4Co6 cuboctahedra that share corners with four equivalent FeHo2Fe2Co8 cuboctahedra, corners with twenty CoHo2Fe4Co6 cuboctahedra, edges with two equivalent FeHo2Fe2Co8 cuboctahedra, edges with three CoHo3Fe3Co6 cuboctahedra, faces with four equivalent FeHo2Fe2Co8 cuboctahedra, and faces with seventeen CoHo2Fe4Co6 cuboctahedra. There are a spread of Co–Co bond distances ranging from 2.35–2.57 Å. In the second Co site, Co is bonded to three Ho, three Fe, and six Co atoms to form distorted CoHo3Fe3Co6 cuboctahedra that share corners with five equivalent FeHo2Fe2Co8 cuboctahedra, corners with eighteen CoHo3Fe3Co6 cuboctahedra, edges with three equivalent FeHo2Fe2Co8 cuboctahedra, edges with seven CoHo3Fe3Co6 cuboctahedra, faces with two equivalent FeHo2Fe2Co8 cuboctahedra, and faces with eighteen CoHo2Fe4Co6 cuboctahedra. Both Co–Co bond lengths are 2.39 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2021

A kinetic evaluation on NO 2 formation in the post-flame region of pressurized oxy-combustion process

Pressurized oxy-combustion is a promising technology that can significantly re-duce the energy penalty associated with first generation oxy-combustion for CO 2 capture in coal-fired power plants. However, higher pressure enhances the production of strong acid gases, including NO 2 and SO 3 , aggravating the corrosion threat during flue gas re-circulation. In the flame region, high temperature NO x exists mainly as NO, while conversion from NO to NO 2 happened in post-flame region. In this study, the conversion of NO → NO 2 has been kinetically evaluated under representative post-flame conditions of pressurized oxy-combustion after validating the mechanism (80 species and 464 reactions), which includes nitrogen and sulfur chemistry based on GRI-MECH 3.0. The effects of residence time, temperature, pressure, major species (O 2 /H 2 O), and minor or trace species (CO/SO x ) on NO 2 formation are studied. The calculation results show that when pressure is increased from 1 to 15 bar, NO 2 is increased from 1 to 60 ppm, and the acid dew point increases by over 80°C. Higher pressure and temperature greatly reduce the time required to reach equilibrium. With increasing pressure and decreasing temperature, O plays a much more important role than HO 2 in the oxidation of NO. A higher water vapor content accelerates NO 2 formation in all cases by providing more O and HO 2 radicals. The addition of CO or SO 2 also promotes the formation of NO 2 . The NO 2 formation in a pressurized oxy-combustion furnace can be over 10 times that of an atmospheric air-combustion furnace.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2023

Hydrophobic Nanoconfinement Enhances CO 2 Conversion to H 2 CO 3

Understanding the formation of H 2 CO 3 in water from CO 2 is important in environmental and industrial processes. Although numerous investigations have studied this reaction, the conversion of CO 2 to H 2 CO 3 in nanopores, and how it differs from that in bulk water, has not been understood. We use ReaxFF metadynamics molecular simulations to demonstrate striking differences in the free energy of CO 2 conversion to H 2 CO 3 in bulk and nanoconfined aqueous environments. We find that nanoconfinement not only reduces the energy barrier but also reverses the reaction from endothermic in bulk water to exothermic in nanoconfined water. Also, charged intermediates are observed more often under nanoconfinement than in bulk water. Stronger solvation and more favorable proton transfer with increasing nanoconfinement enhance the thermodynamics and kinetics of the reaction. Here our results provide a detailed mechanistic understanding of an important step in the carbonation process, which depends intricately on confinement, surface chemistry, and CO 2 concentration.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Materials Data on Ho5CoBi2 by Materials Project

Ho5CoBi2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are four inequivalent Ho sites. In the first Ho site, Ho is bonded to one Co and four equivalent Bi atoms to form a mixture of distorted corner, edge, and face-sharing HoCoBi4 trigonal bipyramids. The Ho–Co bond length is 2.69 Å. All Ho–Bi bond lengths are 3.20 Å. In the second Ho site, Ho is bonded in a 5-coordinate geometry to one Co and four equivalent Bi atoms. The Ho–Co bond length is 2.66 Å. There are two shorter (3.24 Å) and two longer (3.28 Å) Ho–Bi bond lengths. In the third Ho site, Ho is bonded in a 2-coordinate geometry to two equivalent Co and three equivalent Bi atoms. There are one shorter (2.80 Å) and one longer (2.85 Å) Ho–Co bond lengths. There are a spread of Ho–Bi bond distances ranging from 3.36–3.53 Å. In the fourth Ho site, Ho is bonded to one Co and four equivalent Bi atoms to form a mixture of distorted corner, edge, and face-sharing HoCoBi4 trigonal bipyramids. The Ho–Co bond length is 2.98 Å. There are two shorter (3.15 Å) and two longer (3.19 Å) Ho–Bi bond lengths. Co is bonded to seven Ho atoms to form distorted edge-sharing CoHo7 pentagonal bipyramids. Bi is bonded in a 9-coordinate geometry to nine Ho atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho(CoB)2 by Materials Project

HoCo2B2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho3+ is bonded in a body-centered cubic geometry to eight equivalent B3- atoms. All Ho–B bond lengths are 2.87 Å. Co+1.50+ is bonded to four equivalent B3- atoms to form a mixture of edge and corner-sharing CoB4 tetrahedra. All Co–B bond lengths are 2.01 Å. B3- is bonded in a 4-coordinate geometry to four equivalent Ho3+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho3Co by Materials Project

Ho3Co is Cementite structured and crystallizes in the orthorhombic Pnma space group. The structure is two-dimensional and consists of two Ho3Co sheets oriented in the (0, 0, 1) direction. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 2-coordinate geometry to two equivalent Co atoms. There are one shorter (2.73 Å) and one longer (2.82 Å) Ho–Co bond lengths. In the second Ho site, Ho is bonded in a distorted bent 150 degrees geometry to two equivalent Co atoms. There are one shorter (2.67 Å) and one longer (2.75 Å) Ho–Co bond lengths. Co is bonded in a 6-coordinate geometry to six Ho atoms.

36 MATERIALS SCIENCE↗