Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “TiO”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

3D Printed TiO 2 Negative Electrodes for Sodium-Ion and Lithium-ion Batteries using Vat Photopolymerization

Additive manufacturing, also called 3D printing, represents a unique approach to develop three dimensional shape-conformable batteries with enhanced electrodes, specific surface area, improved ion diffusion, and power. For the first time, the formulation of a composite photocurable resin loaded with battery electrochemically active components was designed to feed a vat photopolymerization (VPP) 3D printer. In direct alignment with NASA’s Artemis mission goals to develop sustainable lunar energy storage infrastructure necessary to support long-term human operations, TiO 2 was here selected as an active material for the negative electrode for sodium-ion and lithium-ion batteries due to its abundance on the lunar surface. The TiO 2 loading in the composite photocurable resin and in the resulting VPP-printed negative electrode was increased as high as possible to enhance the electrochemical performance, while simultaneously ensuring the printability and acceptable mechanical strength for sample handling. The effect of thermal post-processing on the electrical, electrochemical and mechanical performance is reported. Finally, a configurational study is implemented to identify the impact of two different electrode designs (cubic and gyroid lattice unit cells) on the electrochemical performance. This work addresses the difficulties related to the introduction of solid particles within a VPP photocurable resin and the need for a compromise between the electrochemical performances and printability to obtain fully functional VPP-printed electrodes.

sodium-ion battery↗
DOE OSTI2023

Insights into Acetic Acid Binding and Ketene Formation on Anatase TiO 2 (101)

Understanding the adsorption and reactivity of carboxylic acids on oxide surfaces is of great interest in catalysis for biomass upgrading via ketonization, a carbon–carbon coupling reaction. Herein, we investigate the adsorption and reaction of acetic acid on anatase TiO 2 (101) using scanning tunneling microscopy, infrared spectroscopy, temperature programmed reaction, and density functional theory calculations. We demonstrate the adsorption of acetic acid can form two intermediates: (1) dissociated, bidentate acetate with an associated bridging hydroxyl, and (2) molecular, monodentate acetic acid. The coexistence of ordered phases with increasing monolayer (ML) saturation coverages consisting of (1) pure acetate (0.5 ML), (2) mixed acetate/acetic acid (0.67 ML), (3) mixed acetate/acetic acid (1.0 ML) and (4) pure acetic acid demonstrates similar energetics for both acetate and acetic acid species. Under ultra-high vacuum conditions, the presence of both monodentate acetic acid and bidentate acetate was observed below room temperature, while solely bidentate acetate was observed up to 575 K. The deprotonation of acetic acid produces water at 280 K, while the thermal decomposition of bidentate acetate produces ketene and acetic acid at 645 K. In conclusion, this model study provides detailed insight into the stability and reactivity of carboxylic acid surface-bound intermediates, which could participate during ketonization reactions for biomass upgrading.

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

Maximizing dynamic range and performance of anatase TiO 2 ECRAM through structure and programming

Here, in this study, we investigate the structure-dependent modulation characteristics of all-solid-state three-terminal electrochemical random-access memory (ECRAM) based on an anatase Li x TiO 2 channel. By directly comparing “asymmetric” and “symmetric” ECRAM device architectures, we reveal significant insight into the impact of a non-zero gate-drain open-circuit voltage and its influence on voltage vs. current-controlled gating. We also explore the impact of potentiation/depression write parameters on the symmetry, linearity, and dynamic range of the device response. Together, initial results from optimizing structure and programming approaches yielded unprecedented G max /G min ratios of >1,000 for ECRAM and hundreds of tunable memory states with excellent linearity and symmetry. Simulations based on these ECRAM devices further illustrate the promise of this analog memory technology, achieving near 2% classification error in the MNIST digit recognition benchmark for a range of training parameters compared to a theoretical best of 1.66% and outperforming other device models extracted from the literature.

AIHWKit↗
DOE OSTI2020

Effect of oxidation post treatments on TiO 2 coating manufactured using reactive very low-pressure plasma spraying (R-VLPPS)

TiO 2 coatings manufactured using reactive very low-pressure plasma spraying (R-VLPPS) were analyzed in different regions related to their position compared to the plasma flame. For that, a screen was used in order to hide an area of the substrate from the direct plasma flux. The coating morphology changed from quasi lamellar structure to highly vapor structure and coatings exhibited obvious modifications in terms of phases and mechanical properties. The effect of oxidation post treatment on the as sprayed coating was then studied by selecting two methods: in situ oxidation post treatment and classical thermal treatment. The two post treatments provided an increase of the main rutile phase and a decrease of both the size and the contents of porosity simultaneously.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Orientation of acetic acid hydrogen bonded to acetate terminated TiO 2 (110)

Acetic acid is a common pollutant for which photocatalytic degradation over titania provides a mitigating strategy. Knowledge of the bonding of acetate/acetic acid to this substrate is needed to aid interpretation of the photocatalytic data. In this work we use ambient pressure near edge X-ray absorption fine structure to measure the coverage and geometry of acetate in the TiO 2 (110) contact layer as well as acetic acid in an additional layer. A saturation coverage of 0.5 monolayers in both layers is found up to an acetic acid pressure of 10 -1 Torr at 266 K. The geometry of acetate appears to be unchanged by adsorption of an additional layer of acetic acid, with the contact layer involving a majority acetate species bidentate bonded to neighboring Ti 5c sites and a minority acetate species bonded in a perpendicular geometry. Acetic acid has a similar geometry dictated by hydrogen bonding to the contact layer as well as the substrate.

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

Materials Data on TiO by Materials Project

TiO crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ti2+ sites. In the first Ti2+ site, Ti2+ is bonded to five O2- atoms to form a mixture of corner and edge-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 2.00–2.15 Å. In the second Ti2+ site, Ti2+ is bonded to five O2- atoms to form a mixture of corner and edge-sharing TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 2.06–2.13 Å. In the third Ti2+ site, Ti2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.06 Å) and two longer (2.12 Å) Ti–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a square co-planar geometry to four Ti2+ atoms. In the second O2- site, O2- is bonded to five Ti2+ atoms to form a mixture of corner and edge-sharing OTi5 square pyramids. In the third O2- site, O2- is bonded to five Ti2+ atoms to form a mixture of corner and edge-sharing OTi5 square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiO by Materials Project

TiO is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ti2+ is bonded to six equivalent O2- atoms to form a mixture of edge and corner-sharing TiO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ti–O bond lengths are 2.14 Å. O2- is bonded to six equivalent Ti2+ atoms to form a mixture of edge and corner-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiOs by Materials Project

TiOs is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ti2+ is bonded in a body-centered cubic geometry to eight equivalent Os2- atoms. All Ti–Os bond lengths are 2.68 Å. Os2- is bonded in a body-centered cubic geometry to eight equivalent Ti2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiO by Materials Project

TiO crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are twelve inequivalent Ti2+ sites. In the first Ti2+ site, Ti2+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four TiO6 octahedra, corners with two equivalent TiO5 square pyramids, an edgeedge with one TiO6 octahedra, and edges with nine TiO5 square pyramids. The corner-sharing octahedra tilt angles range from 9–17°. There are a spread of Ti–O bond distances ranging from 2.06–2.17 Å. In the second Ti2+ site, Ti2+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent TiO5 square pyramids, edges with ten TiO6 octahedra, and edges with two equivalent TiO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.11 Å) and four longer (2.14 Å) Ti–O bond lengths. In the third Ti2+ site, Ti2+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, corners with four equivalent TiO5 square pyramids, edges with ten TiO6 octahedra, and edges with two equivalent TiO5 square pyramids. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.13 Å) and four longer (2.14 Å) Ti–O bond lengths. In the fourth Ti2+ site, Ti2+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with two equivalent TiO6 octahedra, corners with five TiO5 square pyramids, edges with seven TiO6 octahedra, and an edgeedge with one TiO5 square pyramid. The corner-sharing octahedra tilt angles range from 17–19°. There are a spread of Ti–O bond distances ranging from 2.10–2.17 Å. In the fifth Ti2+ site, Ti2+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with two equivalent TiO6 octahedra, corners with five TiO5 square pyramids, edges with seven TiO6 octahedra, and an edgeedge with one TiO5 square pyramid. The corner-sharing octahedra tilt angles range from 16–19°. There are a spread of Ti–O bond distances ranging from 2.09–2.18 Å. In the sixth Ti2+ site, Ti2+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six TiO6 octahedra, edges with seven TiO6 octahedra, and edges with four TiO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–17°. There are a spread of Ti–O bond distances ranging from 2.08–2.23 Å. In the seventh Ti2+ site, Ti2+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with four equivalent TiO6 octahedra, edges with eight TiO6 octahedra, and edges with four TiO5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Ti–O bond distances ranging from 2.10–2.18 Å. In the eighth Ti2+ site, Ti2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.02 Å) and two longer (2.10 Å) Ti–O bond lengths. In the ninth Ti2+ site, Ti2+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with five TiO5 square pyramids, edges with two equivalent TiO6 octahedra, and edges with five TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 2.06–2.15 Å. In the tenth Ti2+ site, Ti2+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with five TiO5 square pyramids, edges with two equivalent TiO6 octahedra, and edges with five TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 2.13–2.18 Å. In the eleventh Ti2+ site, Ti2+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with two equivalent TiO6 octahedra, corners with five TiO5 square pyramids, and edges with five TiO5 square pyramids. The corner-sharing octahedral tilt angles are 9°. There are a spread of Ti–O bond distances ranging from 2.05–2.16 Å. In the twelfth Ti2+ site, Ti2+ is bonded to five O2- atoms to form TiO5 square pyramids that share corners with five TiO5 square pyramids, an edgeedge with one TiO6 octahedra, and edges with five TiO5 square pyramids. There are a spread of Ti–O bond distances ranging from 2.01–2.14 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded to six Ti2+ atoms to form OTi6 octahedra that share corners with six OTi6 octahedra, edges with seven OTi6 octahedra, and edges with four OTi5 square pyramids. The corner-sharing octahedra tilt angles range from 0–17°. In the second O2- site, O2- is bonded to six Ti2+ atoms to form OTi6 octahedra that share corners with four equivalent OTi6 octahedra, edges with eight OTi6 octahedra, and edges with four OTi5 square pyramids. The corner-sharing octahedra tilt angles range from 0–3°. In the third O2- site, O2- is bonded to six Ti2+ atoms to form OTi6 octahedra that share corners with four OTi6 octahedra, corners with two equivalent OTi5 square pyramids, an edgeedge with one OTi6 octahedra, and edges with nine OTi5 square pyramids. The corner-sharing octahedra tilt angles range from 9–17°. In the fourth O2- site, O2- is bonded to five Ti2+ atoms to form OTi5 square pyramids that share corners with two equivalent OTi6 octahedra, corners with five OTi5 square pyramids, edges with seven OTi6 octahedra, and an edgeedge with one OTi5 square pyramid. The corner-sharing octahedral tilt angles are 16°. In the fifth O2- site, O2- is bonded to five Ti2+ atoms to form OTi5 square pyramids that share corners with two equivalent OTi6 octahedra, corners with five OTi5 square pyramids, edges with seven OTi6 octahedra, and an edgeedge with one OTi5 square pyramid. The corner-sharing octahedra tilt angles range from 15–16°. In the sixth O2- site, O2- is bonded to six Ti2+ atoms to form OTi6 octahedra that share corners with two equivalent OTi6 octahedra, corners with four equivalent OTi5 square pyramids, edges with ten OTi6 octahedra, and edges with two equivalent OTi5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the seventh O2- site, O2- is bonded to six Ti2+ atoms to form OTi6 octahedra that share corners with two equivalent OTi6 octahedra, corners with four equivalent OTi5 square pyramids, edges with ten OTi6 octahedra, and edges with two equivalent OTi5 square pyramids. The corner-sharing octahedral tilt angles are 0°. In the eighth O2- site, O2- is bonded to five Ti2+ atoms to form OTi5 square pyramids that share corners with two equivalent OTi6 octahedra, corners with five OTi5 square pyramids, and edges with five OTi5 square pyramids. The corner-sharing octahedra tilt angles range from 9–13°. In the ninth O2- site, O2- is bonded to five Ti2+ atoms to form OTi5 square pyramids that share corners with five OTi5 square pyramids, an edgeedge with one OTi6 octahedra, and edges with five OTi5 square pyramids. In the tenth O2- site, O2- is bonded to five Ti2+ atoms to form OTi5 square pyramids that share corners with five OTi5 square pyramids, edges with two equivalent OTi6 octahedra, and edges with five OTi5 square pyramids. In the eleventh O2- site, O2- is bonded to five Ti2+ atoms to form OTi5 square pyramids that share corners with five OTi5 square pyramids, edges with two equivalent OTi6 octahedra, and edges with five OTi5 square pyramids. In the twelfth O2- site, O2- is bonded in a square co-planar geometry to four Ti2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiO by Materials Project

TiO is Tungsten Carbide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ti2+ is bonded to six equivalent O2- atoms to form a mixture of distorted corner and edge-sharing TiO6 pentagonal pyramids. All Ti–O bond lengths are 2.16 Å. O2- is bonded to six equivalent Ti2+ atoms to form a mixture of corner, edge, and face-sharing OTi6 octahedra. The corner-sharing octahedral tilt angles are 45°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiO by Materials Project

TiO is Tungsten Carbide structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ti2+ is bonded to six equivalent O2- atoms to form a mixture of distorted corner, edge, and face-sharing TiO6 pentagonal pyramids. All Ti–O bond lengths are 2.16 Å. O2- is bonded to six equivalent Ti2+ atoms to form a mixture of distorted corner, edge, and face-sharing OTi6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiO by Materials Project

TiO crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ti2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Ti–O bond lengths are 2.04 Å. O2- is bonded in a square co-planar geometry to four equivalent Ti2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiO by Materials Project

TiO crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are two inequivalent Ti2+ sites. In the first Ti2+ site, Ti2+ is bonded to six equivalent O2- atoms to form a mixture of distorted edge, face, and corner-sharing TiO6 pentagonal pyramids. All Ti–O bond lengths are 2.11 Å. In the second Ti2+ site, Ti2+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All Ti–O bond lengths are 1.98 Å. O2- is bonded to five Ti2+ atoms to form a mixture of distorted edge and corner-sharing OTi5 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Strain‐Driven Mixed‐Phase Domain Architectures and Topological Transitions in Pb 1− x Sr x TiO 3 Thin Films

Abstract The potential for creating hierarchical domain structures, or mixtures of energetically degenerate phases with distinct patterns that can be modified continually, in ferroelectric thin films offers a pathway to control their mesoscale structure beyond lattice‐mismatch strain with a substrate. Here, it is demonstrated that varying the strontium content provides deterministic strain‐driven control of hierarchical domain structures in Pb 1− x Sr x TiO 3 solid‐solution thin films wherein two types, c / a and a 1 / a 2 , of nanodomains can coexist. Combining phase‐field simulations, epitaxial thin‐film growth, detailed structural, domain, and physical‐property characterization, it is observed that the system undergoes a gradual transformation (with increasing strontium content) from droplet‐like a 1 / a 2 domains in a c / a domain matrix, to a connected‐labyrinth geometry of c / a domains, to a disconnected labyrinth structure of the same, and, finally, to droplet‐like c / a domains in an a 1 / a 2 domain matrix. A relationship between the different mixed‐phase modulation patterns and its topological nature is established. Annealing the connected‐labyrinth structure leads to domain coarsening forming distinctive regions of parallel c / a and a 1 / a 2 domain stripes, offering additional design flexibility. Finally, it is found that the connected‐labyrinth domain patterns exhibit the highest dielectric permittivity.

Kavle, Pravin↗
DOE OSTI2024

Flux Synthesis of A-site Disordered Perovskite La 0.5 M 0.5 TiO 3 (M$=$Li, Na, K) Nanorods Tailored for Solid Composite Electrolytes

Inorganic fillers play an important role in improving the ionic conductivity of solid composite electrolytes (SCEs) for Li-ion batteries. Among inorganic fillers, perovskite-type lithium lanthanum titanate (LLTO) stands out for its high bulk Li + conductivity on the order of 10 -3 S cm -1 at room temperature. According to a literature survey, the optimal LLTO filler should possess the following characteristics: i) a single-crystal structure to minimize grain boundaries; ii) a small particle size to increase the filler/polymer interface area; iii) a 1D morphology for efficient interface channels; and iv) cubic symmetry to facilitate rapid bulk Li + diffusion within the filler. However, the synthesis of single crystal, 1D LLTO nanomaterials with cubic symmetry is challenging. Herein, a flux strategy is developed to synthesize La 0.5 M 0.5 TiO 3 (LMTO, M$=$Li, Na, and K) single-crystal nanorods with an A-site-disordered, cubic perovskite phase. The flux media promotes the oriented growth of nanorods, prevents nanorods from sintering, and provides multiple alkali metal ion doping at M sites to stabilize the cubic phase. SCEs compositing the Li + -conducting LMTO nanorods as fillers and poly[vinylene carbonate- co -lithium sulfonyl(trifluoromethane sulfonyl)imide methacrylate] matrix exhibit more than twice the conductivity of the neat polymer electrolyte (30.6 vs 14.0 µS cm -1 at 303 K).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

The Effect of Surface Terminations on the Initial Stages of TiO 2 Deposition on Functionalized Silicon

As atomic layer deposition (ALD) emerges as a method to fabricate architectures with atomic precision, emphasis is placed on understanding surface reactions and nucleation mechanisms. ALD of titanium dioxide with TiCl 4 and water has been used to investigate deposition processes in general, but the effect of surface termination on the initial TiO 2 nucleation lacks needed mechanistic insights. Here, this work examines the adsorption of TiCl 4 on Cl–, H–, and HO– terminated Si(100) and Si(111) surfaces to elucidate the general role of different surface structures and defect types in manipulating surface reactivity of growth and non-growth substrates. The surface sites and their role in the initial stages of deposition are examined by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Density functional theory (DFT) computations of the local functionalized silicon surfaces suggest oxygen-containing defects are primary drivers of selectivity loss on these surfaces.

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

Partial oxidation of isobutylene using Ni TiO x

In this work, we report an aerobic partical oxidation of isobutylene into isoprene, acetone, and p-xylene using a mesoporous Ni TiO x catalytic material. In this work, two catalysts were found to synthesize two of these three valuable products with high selectivity, with p-xylene being synthesized with a selectivity of 46.0% and isoprene being synthesized with a selectivity of 64.7%, with overall conversions of isobutylene being 34.0% and 11.9% respectively. These reactions were done at relatively low temperatures. (300°C or below) and are conducted at flow rates of 10 sccm oxygen and isobutylene. The nickel titania catalysts were studied extensively using various characterization methodologies such as TEM, Raman, XRD, and XRF.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

TiO x -supported Na-Mn-W oxides for the oxidative coupling of methane

Supported Na-Mn-W oxides are among the most studied catalysts for the oxidative coupling of methane (OCM) because of their superior thermal stability and relatively high C 2+ product yields. However, because of the structural complexity, the roles of each component in these catalysts have been controversial. In this work, WO x and MnO x sites were supported on titanate nanowires and employed in OCM studies. Compared to the commonly studied silica support, which is subject to severe restructuring due to the Na-induced crystallization, titanate support not only serves as a reservoir for alkali metals (e.g., Na), but also stabilizes isolated MnO x species. The catalytic performance of the titanate-based catalyst is similar to that of reference catalyst, MnO x /Na 2 WO 4 /SiO 2 , with a synergistic effect between MnO x and WO x sites. Further, advanced electron microscopy, X-ray diffraction, infrared spectroscopy, and X-ray absorption near edge structure spectroscopy suggest that the basic NaO x and MnO x species have strong interactions with the acidic WO x and TiO x species, which might contribute to the high selectivity toward C 2+ products and suppressed CO x formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗