Competitive Reactions and Heat Transfer Effects Applicable to Thermal Runaway Onset in Lithium-Ion Batteries.
Abstract not provided.
Shurtz, Randy↗
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Modeling Competitive Reactions and Heat Transfer Effects Applicable to Thermal Runaway in Lithium-Ion Batteries.
Abstract not provided.
Shurtz, Randy↗
Two Ligands of Interest in Recovering Uranium from the Oceans: The Correct Formation Constants of the Uranyl(VI) Cation with 2,2'-Bipyridyl-6,6'-dicarboxylic Acid and 1,10-Phenanthroline-2,9-dicarboxylic Acid
The ligands BDA (2,2'-bipyridyl-6,6'-dicarboxylic acid) and PDA (1,10-phenanthroline-2,9-dicarboxylic acid) are of interest as functional group types for ion-exchange materials for extracting uranium from the oceans, reported in a previous paper for PDA Lashley, M. A. ( Inorg. Chem. 2016 55 10818 10829). Yang, Y. ( Inorg. Chem. 2019, 58, 6064 6074) have published what they claim to be a more accurate result for the formation of the UO 2 2+ /PDA complex of log K 1 = 22.84 compared with our reported value of log K 1 = 16.5, as well as log K 1 = 21.52 for the BDA complex. The determination of log K 1 for the PDA and BDA complexes with the UO 2 2+ cation was carried out by Yang et al. using a competition reaction between DTPA (diethylenetriamine pentaacetic acid) and BDA or PDA, monitoring the absorbance due to the BDA and PDA ligands. This competition method using absorbance versus pH titrations was developed for determining the formation constants of the complexes of several polypyridyl ligands plus PDA complexes of metal ions, which were too stable for log K determination by competition with protons. A key feature of such titrations is that in the competition reaction, the displacement of the pyridyl donor ligand (e.g., PDA) by the competing ligand (e.g., DTPA), the absorbance spectrum of the displaced pyridyl donor ligand should be observed. Competing ligands used to date have been EDTA (ethylenediamine tetraacetic acid), DTPA, or the hydroxide ion. In the study of Yang et al., no such displaced PDA or BDA was apparent in the absorbance spectra in their titrations so that their reported log K 1 values have no validity. Their log K 1 values are so much higher than log K 1 for the uranyl DTPA complex (~13.6) that DTPA could not possibly displace BDA or PDA from the uranyl cation, and a competition reaction could not possibly occur. Here, we report the correct value of log K 1 = 15.4 (ionic strength = zero) for the uranyl BDA complex, to illustrate the correct determination of such a constant by a competition reaction between BDA and hydroxide, showing how the characteristic absorbance spectrum for a BDA complex, here the UO 2 2+ complex, disappears, and the distinctive absorbance spectrum of the free nonprotonated BDA ligand appears as the pH is increased, and BDA is displaced by the hydroxide ion.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Comprehensive insights into competitive oxidation/sulfidation reactions on binary ferritic alloys at high temperatures
Interpreting high-temperature corrosion induced by mixed-gas atmospheres is challenging due to the different contributions of oxidizing gases. In this work, a comprehensive study on the combined oxidation/sulfidation using label molecules is presented. Fe-Cr model alloys with 2 wt% and 9 wt% Cr were isothermally exposed using a volumetric mixture of 0.5%S 16 O 2 /27%H 2 18 O and 0.5%S 16 O 2 /7%H 2 18 O at 650 °C for 5 h and then characterized by secondary ion mass spectroscopy (SIMS). Additionally, the reactions were followed in-situ utilizing energy dispersive X-ray diffraction. The study showed that both S 16 O 2 and H 2 18 O contribute to the oxidation of the alloys but to different extents depending on the Cr-content.
36 MATERIALS SCIENCE↗
Effects of iron carbide crystal phases and dopants on the conversions of CO 2 into ethylene
The density functional theory method was used to investigate the conversions of CO 2 to ethylene formation on two common iron carbide surfaces: Fe 3 C(0 1 0) and Fe 5 C 2 (1 1 1). Based on the structure relaxation of reaction intermediates and the elementary reaction transition states. We deduced the most competitive reaction pathways for ethylene production. The main CO 2 -to-ethylene routes and the competition of side products, CO and CH 4 , are discussed. Our analyses showed that CO 2 conversion is surface structure sensitive, whereas CH 4 and C2+ hydrocarbon formations depend on the reactivity of native C atoms in the carbides. To modify the intrinsic catalyst performance, mixing dopants in Fe catalysts is an effective strategy. Furthermore, we demonstrate that doping Zn and Zr can alter the local electronic structure and enhance CO 2 adsorption on the catalyst surface.
CO2 hydrogenation↗
Understanding Reaction Networks through Controlled Approach to Equilibrium Experiments Using Transient Methods
We report a combined experimental/theoretical approach to studying heterogeneous gas/solid catalytic processes using low-pressure pulse response experiments achieving a controlled approach to equilibrium that combined with quantum mechanics (QM)-based computational analysis provides information needed to reconstruct the role of the different surface reaction steps. We demonstrate this approach using model catalysts for ammonia synthesis/decomposition. Polycrystalline iron and cobalt are studied via low-pressure TAP (temporal analysis of products) pulse response, with the results interpreted through reaction free energies calculated using QM on Fe-BCC(110), Fe-BCC(111), and Co-FCC(111) facets. In TAP experiments, simultaneous pulsing of ammonia and deuterium creates a condition where the participation of reactants and products can be distinguished in both forward and reverse reaction steps. This establishes a balance between competitive reactions for D* surface species that is used to observe the influence of steps leading to nitrogen formation as the nitrogen product remains far from equilibrium. Here, the approach to equilibrium is further controlled by introducing delay timing between NH 3 and D 2 which allows time for surface reactions to evolve before being driven in the reverse direction from the gas phase. The resulting isotopic product distributions for NH 2 D, NHD 2 , and HD at different temperatures and delay times and NH 3 /D 2 pulsing order reveal the role of the N 2 formation barrier in controlling the surface concentration of NH x * species, as well as providing information on the surface lifetimes of key reaction intermediates. Conclusions derived for monometallic materials are used to interpret experimental results on a more complex and active CoFe bimetallic catalyst.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Coupling hydropyrolysis and vapor-phase catalytic hydrotreatment to produce biomethane from pine sawdust
Here, this study investigated hydropyrolysis and subsequent vapor-phase hydrotreatment over a NiAl 2 O 4 catalyst to produce biomethane (CH 4 ) from pine sawdust. The non-catalytic pressurized hydropyrolysis generated tar, CO 2 , and CO as the primary products. However, using a NiAl 2 O 4 catalyst in the second-stage reactor significantly increased the formation of CH 4 and reduced CO and CO 2 in gas products. The catalyst also fully converted tar intermediates to produce CH 4 , resulting in a maximum carbon yield of 77.7% with 97.8% selectivity. The temperature plays a crucial role in CH 4 generation, with both its yield and selectivity showing a positive correlation with the reaction temperature. Increasing the reaction pressure from 0.2 to 1.2 MPa notably inhibited the production of CH 4 , leading to a shift towards cycloalkanes due to a competitive reaction. This tandem approach shows great potential as an innovative technique for producing alternative fuels from biomass wastes.
09 BIOMASS FUELS↗
Converting polyisoprene rubbers into bio-jet fuels via a cascade hydropyrolysis and vapor-phase hydrogenation process
Producing alternative drop-in bio-jet fuels from biomass provides a promising approach to achieve carbon neutrality. Here, to upcycle biomass-based polyisoprene rubbers into jet-fuel range C 10 cycloalkane, we proposed a cascade hydropyrolysis and vapor-phase hydrogenation process in a flow-through two-stage pressurized fixed-bed reactor. The hydropyrolysis temperature in the first stage is of vital importance for the formation of primary limonene intermediate in the non-catalytic degradation of polyisoprene rubbers, and a reaction temperature of 460 °C maximized limonene yield to 588.6 mg/g for natural rubber and 546.2 mg/g for Eucommia rubber. Over a Pt/C catalyst loaded in the second stage, the limonene intermediate produced from the first-stage reactor can be completely hydrogenated, giving a 642.7 mg/g yield of jet-fuel range C 10 cycloalkane with 83.6% selectivity. The depolymerization mechanism of polyisoprene rubbers was thoroughly studied, and a competitive reaction between limonene hydrogenation and limonene dehydrogenation was observed. This is the first report on producing C 10 cycloalkane from natural rubbers via a cascade hydropyrolysis and hydrogenation process, providing a promising strategy to upcycle polyisoprene rubbers into bio-jet fuels.
30 DIRECT ENERGY CONVERSION↗
Tailoring olefin distribution via tuning rare earth metals in bifunctional Cu-RE/beta-zeolite catalysts for ethanol upgrading
Bioethanol to middle distillate technologies have offered a unique solution to produce renewable aviation fuel for decarbonizing the hard-to-electrify sectors. Here, we have developed the series of bimetallic Cu- and rare earth-containing (RE) Beta zeolite catalysts that yield high C 3+ alkene selectivity from ethanol upgrading (>80% selectivity at ~100% conversion, 623 K). The formation rates of butene isomers to C 5+ alkenes are linearly correlated with the strength of Lewis acidic RE identity, which follows the sequence of Yb 12 /Beta >Y 7 /Beta > Gd 12 /Beta > Ce 10 /Beta > La 12 /Beta. Rate measurements indicate that the RE selection plays the vital role in altering the rate of the key competitive reactions within the ethanol-to-alkenes reaction network, namely C 4 alcohol dehydration and C-C chain growth, which dictate alkene product distributions. Finally, these findings indicate a feasible and promising method for tailoring alkene product distributions from ethanol upgrading, which is of notable significance to the generation of renewable middle distillates.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Converting polycarbonate and polystyrene plastic wastes intoaromatic hydrocarbons via catalytic fast co-pyrolysis
Thermochemical conversion of plastic wastes is a promising approach to produce alternative energy-based fuels. Herein, we conducted catalytic fast co-pyrolysis of polycarbonate (PC) and polystyrene (PS) to generate aromatic hydrocarbons using HZSM-5 (Zeolite Socony Mobil-5, hydrogen, Aluminosilicate) as a catalyst. The results indicated that employing HZSM-5 in the catalytic conversion of PC facilitated the synthesis of aromatic hydrocarbons in comparison to the non-catalytic run. A competitive reaction between aromatic hydrocarbons and aromatic oxygenates was observed within the studied temperature region, and catalytic degradation temperature of 700 °C maximized the competing reaction towards the formation of targeted aromatic hydrocarbons at the expense of phenolic products. Catalyst type also played a vital role in the catalytic decomposition of PC wastes, and HZSM-5 with different Si/Al molar ratios produced more aromatic hydrocarbons than HY (Zeolite Y, hydrogen, Faujasite). Regarding the effect of Si/Al molar ration in HZSM-5 on the distribution of monocyclic aromatic hydrocarbons (MAHs), a Si/Al molar ratio of 38 maximized benzene formation with an advanced factor of 5.1. Catalytic fast co-pyrolysis of PC with hydrogen-rich plastic wastes including polypropylene (PP), polyethylene (PE), and polystyrene (PS) favored the production of MAHs, and PS was the most effective hydrogen donor with a ~2.5-fold increase. The additive effect of MAHs increased at first and then decreased when the PC percentage was elevated from 30 % to 90 %, achieving the maximum value of 32.4 % at 70 % PC.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Spatiotemporal and Statistical Mapping of Transition Metal Equilibria in Alkaline Media
Transition metal dissolution and redeposition (D/R) kinetics in alkaline media play a critical role in various chemical and electrochemical processes. Competitive reaction kinetics between different transition metals can modulate individual metal behavior in these processes. To date, these phenomena have remained largely unmeasured, and even when captured, they are difficult to statistically characterize due to their dynamic nature, simultaneous occurrence, and spatially heterogeneous nature. Here, in this study, we develop a statistical analysis framework based on in situ and operando X-ray fluorescence microscopy (XFM) to investigate the relative D/R kinetics of multiple transition metals in alkaline media. By employing statistical analysis, we quantify the spatial distribution of D/R species and assess the rate at which the system reaches equilibrium under varying reaction conditions. We show that pH does not simply change the rate of dissolution and redeposition, but reorganizes the cross-element kinetic correlations among Ni, Fe, and Mn and accelerates the spatial equilibration of D/R events, as quantified through correlation analysis, reaction-rate estimation, probability function distributions, and texture-based monitoring statistics. Additionally, we demonstrate how modifying the solvent environment can influence D/R kinetics, providing a pathway for tuning materials synthesis and process optimization. Our study offers valuable insights into the complex interplay between different transition metals and provides a reliable statistical framework for spatial analysis of diverse imaging data sets, enabling deeper extraction of latent information across multiple modalities.
36 MATERIALS SCIENCE↗
Fracture Dynamics in Silicon Anode Solid-State Batteries
Solid-state batteries (SSBs) with silicon anodes could enable improved safety and energy density compared to lithium-ion batteries. However, degradation arising from the massive volumetric changes of silicon anodes during cycling is not well understood in solid-state systems. Here, we use operando X-ray computed microtomography to reveal micro- to macro-scale chemo-mechanical degradation processes of silicon anodes in SSBs. Mud-type channel cracks driven by biaxial tensile stress form across the electrode during delithiation. We also find detrimental cracks at the silicon/ solid electrolyte interface that form due to local reaction competition between neighboring domains of different sizes. Continuum phase-field damage modeling quantifies stress-driven channel cracking and shows that the lithiated silicon stress state is critical for determining the extent of interfacial fracture. This work reveals the mechanisms that govern SSBs compared to conventional lithium-ion batteries and provides guidelines for engineering chemomechanically resilient electrodes for high-energy batteries.
25 ENERGY STORAGE↗
Reliable bi-functional nickel-phosphate /TiO2 integration enables stable n-GaAs photoanode for water oxidation under alkaline condition
Abstract Hydrogen is one of the most widely used essential chemicals worldwide, and it is also employed in the production of many other chemicals, especially carbon-free energy fuels produced via photoelectrochemical (PEC) water splitting. At present, gallium arsenide represents the most efficient photoanode material for PEC water oxidation, but it is known to either be anodically photocorroded or photopassivated by native metal oxides in the competitive reaction, limiting efficiency and stability. Here, we report chemically etched GaAs that is decorated with thin titanium dioxide (~30 nm-thick, crystalline) surface passivation layer along with nickel-phosphate (Ni-Pi) cocatalyst as a surface hole-sink layer. The integration of Ni-Pi bifunctional co-catalyst results in a highly efficient GaAs electrode with a ~ 100 mV cathodic shift of the onset potential. In this work, the electrode also has enhanced photostability under 110 h testing for PEC water oxidation at a steady current density J ph > 25 mA·cm −2 . The Et-GaAs/TiO 2 /Ni-Pi║Ni-Pi tandem configuration results in the best unassisted bias-free water splitting device with the highest J ph (~7.6 mA·cm −2 ) and a stable solar-to-hydrogen conversion efficiency of 9.5%.
08 HYDROGEN↗
Power at Sea: Use of Wave Energy Converters for Powering Offshore Oil and Gas Operations
New innovative services and goods based on artificial intelligence, next-generation robotics, autonomy, digitization, and electrification are taking root in the ocean economy. More typical competitive forces, such as value enhancement and safety improvement, are also present, as suppliers constantly strive to improve their competitive positioning. Concurrently, the Oil and Gas sector is experiencing mounting pressure to decrease its operational carbon emissions, forcing efforts to reduce or eliminate liquid fuel consumption offshore. Companies in the ocean economy are having to react to this combination of macro- and micro-level drivers and innovate at an ever more rapid pace. However, before many of these new capabilities can be implemented, new, clean, reliable power sources are needed, especially as liquid fuel grows increasingly out of favor. For many of these loads—both old and new and ranging from watts to megawatts—wave energy systems provide the best solution for remote power generation. As such, research, development and demonstration activities are underway to prove wave energy's ability to provide reliable, consistent energy supplies for certain offshore Oil and Gas activities, paving the way for near term commercialization. Furthermore, this paper outlines these drivers, competitive reaction to them, and why and how wave energy can be a preferable choice for power at sea.
16 TIDAL AND WAVE POWER↗
Localized Corrosion of Chromium-Containing Conventional and Multiprincipal Element Alloys in Methanol and Aqueous Chloride Environments
The localized corrosion behavior of Type 304L stainless steel (UNS S30400), Alloy 625 (UNS N06625), and three experimental NiCoCrMo multiprincipal element alloys (MPEA), exposed to methanol/lithium chloride solutions with different water contents, is examined in this paper. Cyclic potentiodynamic polarization tests indicated that water increased the pitting and repassivation potentials and the critical temperature at which localized corrosion occurred in chloride solutions. The effect of water on repassivation potential in methanol-chloride solution depended on the chloride concentration and alloy content. At lower chloride concentration and higher alloy content, water had a greater inhibiting effect on repassivation potential, suggesting a competitive reaction between chloride and water on the metal surface in the pit. The localized corrosion resistance of the MPEAs followed the same trend as that of commercial stainless steels and Ni-base alloys in terms of the effect of alloying elements. The implications of these results on the mechanisms of localized corrosion are discussed.
Materials Science↗
Nonadiabatic dissociation of molecular Bose-Einstein condensates: Competition between chemical reactions
Here, we provide a framework to solve generic models describing the dissociation of multiple molecular Bose Einstein condensates in a nonadiabatic regime. The competition between individual chemical reactions can lead to non-trivial dependence on critical components such as path interference and symmetries, thus, affecting the final distribution of atomic population. We find an analytical solution for an illustrative example model involving four atomic modes. When the system parameters satisfy CPT symmetry, where C is charge conjugation, P is parity, and T is time-reversal symmetry, our solution predicts a population imbalance between atomic modes that is exponentially sensitive to system parameters. However, a weakly broken symmetry alters the population in each atomic mode and can reverse the population imbalance. Our solution also demonstrates a strong quantum correlation between atomic modes that leads to the spontaneous production of atoms in a multi-mode squeezed state. Moreover, in our framework, a time-dependent non-Hermitian quantum mechanics naturally manifests which can alternatively be realized experimentally in photonic systems.
74 ATOMIC AND MOLECULAR PHYSICS↗
Probing Electrochemical Mg-Ion Activity in MgCr 2– x V x O 4 Spinel Oxides
Mg migration in oxide spinels is impeded by strong affinity between divalent Mg and oxygen, suggesting a necessity of exploring new chemistry of solid lattices for functional Mg-ion electrode materials. Cationic mobility with a suitable activation energy in Cr spinels is Tn. evidenced by theoretical and experimental results, while redox potentials of V are appropriate to operate with currently limited candidates of '''c" nonaqueous electrolytes. By controlling the structure, composition, and complexity, a largely solid-solution MgCrVO 4 spinel was synthesized, which, unlike nanocornposites, can bring together the advantages of each transition metal in the lattice. The spinel was successfully synthesized by a simple solid-state reaction with minor inactive Cr- or V-rich components, which was confirmed via 25 Mg MAS NMR and high-resolution X-ray diffraction analyses. A thermally and anodically stable Mg(TPFA) 2 /triglyme electrolyte was utilized for high-temperature electrochemistry and lowering kinetic barriers at and across interfaces so as to observe intercalation behavior of Mg in the designed lattice. Multimodal characterization confirmed an apparent bulk demagnesiation from MgCrVO 4 with partial reversibility by probing evolution of the local and long-range structure as well as vanadium and chromium electronic states within the lattice. Furthermore, characterization experiments also provided a direct evidence for (de)intercalation reactions that occurred without any major competitive conversion reactions or insertion of protons into the lattice, except for the formation of a surface rock salt phase upon charge. These findings in Mg-ion activity expand opportunities to design Mg spinel oxide materials while highlighting the need to identify the origins of reversibility challenges due to, but not limited to, phase stability, particularly for the charged states, barriers at the interface, electrolyte stabilities, and desolvation phenomena, collectively hindering practical use as cathode materials.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗