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A system and method for improved atomic layer deposition. The system includes a top showerhead plate, a substrate and a bottom showerhead plate. The substrate includes a porous microchannel plate and a substrate holder is positioned in the system to insure flow-through of the gas precursor.
Porous compositions such as flexible polymers with side chain porosity are generally provided. In some embodiments, the composition comprises a flexible polymer backbone and a plurality of rigid side chains. In some embodiments, the rigid side chains form pores. In some embodiments, the rigid side chains may comprise two or more [2.2.2] bicyclic cores (e.g., formed by a ring opening metathesis polymerization. The compounds and methods described herein may be useful in various applications including, for example, gas separation.
The invention relates to composite multilayer lithium ion battery anodes that include a porous metal alloy foam, and a lithium ion conductor coating applied to the metal alloy foam. The metal alloy foam can include structurally isomorphous alloys of lithium and, optionally, lithium and magnesium. The lithium ion conductor coating can include ternary lithium silicate, such as, lithium orthosilicate. Lithium ions from the ternary lithium silicate may be deposited within the pores of the metal alloy foam. Optionally, the lithium ion conductor coating may include a dopant. The dopant can include one or more of magnesium, calcium, vanadium, niobium and fluorine, and mixtures and combinations thereof.
In accordance with one aspect of the presently disclosed inventive concepts, a porous ceramic structure includes a three-dimensional printed structure having predefined features, where the three-dimensional structure has a geometric shape. The average length of the features may be at least 10 microns. The three-dimensional structure includes a ceramic material having an open cell structure with a plurality of pores, where the pores form continuous channels through the ceramic material from one side of the ceramic material to an opposite side of the ceramic material.
The disclosure relates to a brazing method for joining substrates, in particular where one of the substrates is difficult to wet with molten braze material. The method includes formation of a porous metal layer on a first substrate to assist wetting of the first substrate with a molten braze metal, which in turn permits joining of the first substrate with a second substrate via a braze metal later in an assembled brazed joint. Ceramic substrates can be particularly difficult to wet with molten braze metals, and the disclosed method can be used to join a ceramic substrate to another substrate. The brazed joint can be incorporated into a solid-oxide fuel cell, for example as a stack component thereof, in particular when the first substrate is a ceramic substrate and the joined substrate is a metallic substrate.
Thermo-responsive hydrogel composite (TRHC) desiccants having high adsorption capacities, fast adsorption/desorption rates, and low regeneration temperatures (Treg) compared to traditional desiccants. TRHC desiccants may be synthesized by freeze drying. The porous structures resulting from freeze drying copolymers of thermo-responsive polymers and/or hygroscopic agents may be combined with hygroscopic inorganic salts, resulting in TRHC desiccants having superior performance properties.
This disclosure provides compositions and methods directed to thermally stable catalyst systems, which display stable physical properties and/or stable catalytic properties after thermal pretreatment at a temperature in the range of about 600° C. to about 1000° C. The catalyst systems include metal particles which contain a stable metal and a catalytic metal deposited on a porous support. Embodiments of the disclosure include catalyst systems that can be used in high temperature applications such as the hybrid sulfur cycle. The hybrid sulfur cyclic is an elevated temperature and high acid reaction that may be conducted using concentrated sulfuric acid heated to 800° C. Embodiments of the disclosure can provide thermally stable catalysts and methods to produce thermally stable catalysts that remain active for at least 80 hours' exposure to these harsh conditions.
A porous sorbent ceramic product includes a three-dimensional structure having an electrically conductive ceramic material, wherein the conductive ceramic material has an open cell structure with a plurality of intra-material pores, a sorbent additive primarily present in the intra-material pores of the conductive ceramic material for adsorption of a gas, and at least two electrodes in electrical communication with the conductive ceramic material.
A thermo-electrochemical reactive capture apparatus includes an anode and a cathode, wherein the anode includes a first catalyst, wherein the cathode includes a second catalyst, a porous ceramic support positioned between the anode and the cathode, an electrolyte mixture in pores of the ceramic support, and a steam flow system on an outer side of the cathode. The outer side of the cathode is opposite an inner side of the cathode and the inner side of the cathode is adjacent to the ceramic support. In addition, the electrolyte mixture is configured to be molten at a temperature below about 600° C.
Ether-thioether functionalized porous aromatic framework (PAF) polymers provide high selectivity for iron(II) and iron(III) adsorption in aqueous samples.
This work is the first report of a molybdenum carbide-based electrocatalyst for sulfur-based sodium metal batteries (SMBs/NMBs). MoC/Mo 2 C is in-situ grown on nitrogen-doped carbon nanotubes in parallel with formation of extensive nanoporosity. Sulfur impregnation (50 wt% S) results in unique triphasic architecture termed MoC/Mo 2 C@PCNT-S. Quasi-solid-state phase transformation to Na 2 S is promoted in carbonate electrolyte, with in-situ time-resolved Raman, XPS and optical analysis demonstrating minimal soluble polysulfides. MoC/Mo 2 C@PCNT-S cathodes delivered among the most promising rate performance characteristics in literature, achieving 987 mAh g -1 at 1 Ag -1 , 818 mAh g -1 at 3 A g -1 , and 621 mAh g -1 at 5 A g -1 . The cells deliver superior cycling stability, retaining 650 mAh g -1 after 1000 cycles at 1.5 Ag -1 , corresponding to 0.028% capacity decay per cycle. High mass loading cathodes (64 wt% S, 12.7 mg cm -2 ) also show cycling stability, with anode degradation due to deep plating/stripping driving capacity decay. Density functional theory (DFT) demonstrates that formation energy of Na 2 S x (1 ≤ x ≤ 4) on surface of MoC/Mo 2 C is significantly lowered compared to analogous redox in liquid. Strong binding of Na 2 S x (1 ≤ x ≤ 4) on MoC/Mo 2 C surfaces results from charge transfer between the sulfur and Mo sites on carbides' surface.
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Coupling multiphase flow with energy transport due to high temperature heat sources introduces significant new challenges since boiling and condensation processes can lead to dry-out conditions with subsequent re-wetting. The transition between two-phase and single-phase behavior can require changes to the primary dependent variables adding discontinuities as well as extending constitutive nonlinear relations to extreme physical conditions. Practical simulations of large-scale engineered domains lead to Jacobian systems with a very large number of unknowns that must be solved efficiently using iterative methods in parallel on high-performance computers. Performance assessment of potential nuclear repositories, carbon sequestration sites and geothermal reservoirs can require numerous Monte-Carlo simulations to explore uncertainty in material properties, boundary conditions, and failure scenarios. Due to the numerical challenges, standard NR iteration may not converge over the range of required simulations and require more sophisticated optimization method like trust-region. In this study, we use the open-source simulator PFLOTRAN for the important practical problem of the safety assessment of future nuclear waste repositories in the U.S. DOE geologic disposal safety assessment Framework. The simulator applies the PETSc parallel framework and a backward Euler, finite volume discretization. We demonstrate failure of the conventional NR method and the success of trust-region modifications to Newton’s method for a series of test problems of increasing complexity. Trust-region methods essentially modify the Newton step size and direction under some circumstances where the standard NR iteration can cause the solution to diverge or oscillate. Furthermore, we show how the Newton Trust-Region method can be adapted for Primary Variable Switching (PVS) when the multiphase state changes due to boiling or condensation. The simulations with high-temperature heat sources which led to extreme nonlinear processes with many state changes in the domain did not converge with NR, but they do complete successfully with the trust-region methods modified for PVS. This implementation effectively decreased weeks of simulation time needing manual adjustments to complete a simulation down to a day. Finally, we show the strong scalability of the methods on a single node and multiple nodes in an HPC cluster.
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Soil organic matter (SOM) has attracted a great deal of interest; particularly for its potential to mitigate human derived CO 2 emissions. Studies have demonstrated that SOM plays a critical role in carbon storage and CO 2 sequestration. However, the sorption properties of SOM, which influence its transport in pore water and stabilization within the soil, remain poorly understood. This study develops a workflow to: (1) examine compound-specific advective and diffusive transport and desorption behaviors, (2) quantify desorption rates through stop-flow and continuous-flow column experiments, and (3) evaluate the impact of soil microporosity on SOM mobility using high-resolution imaging and extractions. Intact core column experiments were conducted on Uncultivated (Natural) and Cultivated soil samples, both were arid soils, collected in Washington State. X-ray computed tomography was employed to measure porosity and pore connectivity, while Fourier-transform ion cyclotron resonance mass spectrometry was used to analyze SOM composition. The findings revealed that cultivation increased total carbon and nitrogen levels due to irrigation and fertilization, enhancing carbon capture potential in arid soils. In contrast, the Natural soil, characterized by higher porosity and connectivity, contained more oxidized carbon. Pore network analysis indicated that soil compaction in the Cultivated soil may lead to longer diffusion pathways, significantly influencing SOM transport and stability.
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