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1.
Proc Natl Acad Sci U S A ; 121(14): e2316564121, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38527200

RESUMO

Sulfur in nature consists of two abundant stable isotopes, with two more neutrons in the heavy one (34S) than in the light one (32S). The two isotopes show similar physicochemical properties and are usually considered an integral system for chemical research in various fields. In this work, a model study based on a Li-S battery was performed to reveal the variation between the electrochemical properties of the two S isotopes. Provided with the same octatomic ring structure, the cyclo-34S8 molecules form stronger S-S bonds than cyclo-32S8 and are more prone to react with Li. The soluble Li polysulfides generated by the Li-34S conversion reaction show a stronger cation-solvent interaction yet a weaker cation-anion interaction than the 32S-based counterparts, which facilitates quick solvation of polysulfides yet hinders their migration from the cathode to the anode. Consequently, the Li-34S cell shows improved cathode reaction kinetics at the solid-liquid interface and inhibited shuttle of polysulfides through the electrolyte so that it demonstrates better cycling performance than the Li-32S cell. Based on the varied shuttle kinetics of the isotopic-S-based polysulfides, an electrochemical separation method for 34S/32S isotope is proposed, which enables a notably higher separation factor than the conventional separation methods via chemical exchange or distillation and brings opportunities to low-cost manufacture, utilization, and research of heavy chalcogen isotopes.

2.
J Biol Chem ; 300(10): 107745, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39236874

RESUMO

We have investigated the kinetic behavior of the electron-bifurcating crotonyl-CoA-dependent NADH: ferredoxin oxidoreductase EtfAB:bcd from Megasphaera elsdenii. The overall behavior of the complex in both the reductive and the oxidative half-reactions is consistent with that previously determined for the individual EtfAB and bcd components. This includes an uncrossing of the half-potentials of the bifurcating flavin of the EtfAB component in the course of ferredoxin-reducing catalysis, ionization of the bcd flavin semiquinone and the appearance of a charge transfer complex upon binding of the high potential acceptor crotonyl-CoA. The observed rapid-reaction rates of ferredoxin reduction are independent of [NADH], [crotonyl-CoA], and [ferredoxin], with an observed rate of ∼0.2 s-1, consistent with the observed steady-state kinetics. In enzyme-monitored turnover experiments, an approach to steady-state where the complex's flavins become reduced but no ferredoxin is generated is followed by a steady-state phase characterized by extensive ferredoxin reduction but little change in overall levels of flavin reduction. The approach to the steady-state phase can be eliminated by prior reduction of the complex, in which case there is no lag in the onset of ferredoxin reduction; this is consistent with the et FAD needing to be reduced to the level of the (anionic) semiquinone for bifurcation and concomitant ferredoxin reduction to occur. Single-turnover experiments support this conclusion, with the accumulation of the anionic semiquinone of the et FAD apparently required to prime the system for subsequent bifurcation and ferredoxin reduction.

3.
J Biol Chem ; 300(6): 107381, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38762175

RESUMO

Enzymes are potent catalysts that increase biochemical reaction rates by several orders of magnitude. Flavoproteins are a class of enzymes whose classification relies on their ability to react with molecular oxygen (O2) during catalysis using ionizable active site residues. Pseudomonas aeruginosa D-arginine dehydrogenase (PaDADH) is a flavoprotein that oxidizes D-arginine for P. aeruginosa survival and biofilm formation. The crystal structure of PaDADH reveals the interaction of the glutamate 246 (E246) side chain with the substrate and at least three other active site residues, establishing a hydrogen bond network in the active site. Additionally, E246 likely ionizes to facilitate substrate binding during PaDADH catalysis. This study aimed to investigate how replacing the E246 residue with leucine affects PaDADH catalysis and its ability to react with O2 using steady-state kinetics coupled with pH profile studies. The data reveal a gain of O2 reactivity in the E246L variant, resulting in a reduced flavin semiquinone species and superoxide (O2•-) during substrate oxidation. The O2•- reacts with active site protons, resulting in an observed nonstoichiometric slope of 1.5 in the enzyme's log (kcat/Km) pH profile with D-arginine. Adding superoxide dismutase results in an observed correction of the slope to 1.0. This study demonstrates how O2•- can alter the slopes of limbs in the pH profiles of flavin-dependent enzymes and serves as a model for correcting nonstoichiometric slopes in elucidating reaction mechanisms of flavoproteins.


Assuntos
Aminoácido Oxirredutases , Domínio Catalítico , Oxigênio , Pseudomonas aeruginosa , Superóxidos , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/genética , Oxigênio/metabolismo , Oxigênio/química , Superóxidos/metabolismo , Superóxidos/química , Aminoácido Oxirredutases/química , Aminoácido Oxirredutases/metabolismo , Aminoácido Oxirredutases/genética , Prótons , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Cinética , Oxirredução , Mutação , Substituição de Aminoácidos , Arginina/química , Arginina/metabolismo
4.
Proc Natl Acad Sci U S A ; 119(40): e2204666119, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36161954

RESUMO

Given the high energy density and eco-friendly characteristics, lithium-carbon dioxide (Li-CO2) batteries have been considered to be a next-generation energy technology to promote carbon neutral and space exploration. However, Li-CO2 batteries suffer from sluggish reaction kinetics, causing large overpotential and poor energy efficiency. Here, we observe enhanced reaction kinetics in aprotic Li-CO2 batteries with unconventional phase 4H/face-centered cubic (fcc) iridium (Ir) nanostructures grown on gold template. Significantly, 4H/fcc Ir exhibits superior electrochemical performance over fcc Ir in facilitating the round-trip reaction kinetics of Li+-mediated CO2 reduction and evolution, achieving a low charge plateau below 3.61 V and high energy efficiency of 83.8%. Ex situ/in situ studies and theoretical calculations reveal that the boosted reaction kinetics arises from the highly reversible generation of amorphous/low-crystalline discharge products on 4H/fcc Ir via the Ir-O coupling. The demonstration of flexible Li-CO2 pouch cells with 4H/fcc Ir suggests the feasibility of using unconventional phase nanomaterials in practical scenarios.

5.
Proc Natl Acad Sci U S A ; 119(8)2022 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-35165185

RESUMO

Developing heterogeneous catalysts with atomically dispersed active sites is vital to boost peroxymonosulfate (PMS) activation for Fenton-like activity, but how to controllably adjust the electronic configuration of metal centers to further improve the activation kinetics still remains a great challenge. Herein, we report a systematic investigation into heteroatom-doped engineering for tuning the electronic structure of Cu-N4 sites by integrating electron-deficient boron (B) or electron-rich phosphorus (P) heteroatoms into carbon substrate for PMS activation. The electron-depleted Cu-N4/C-B is found to exhibit the most active oxidation capacity among the prepared Cu-N4 single-atom catalysts, which is at the top rankings of the Cu-based catalysts and is superior to most of the state-of-the-art heterogeneous Fenton-like catalysts. Conversely, the electron-enriched Cu-N4/C-P induces a decrease in PMS activation. Both experimental results and theoretical simulations unravel that the long-range interaction with B atoms decreases the electronic density of Cu active sites and down-shifts the d-band center, and thereby optimizes the adsorption energy for PMS activation. This study provides an approach to finely control the electronic structure of Cu-N4 sites at the atomic level and is expected to guide the design of smart Fenton-like catalysts.

6.
Nano Lett ; 24(34): 10547-10553, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39140754

RESUMO

Two-dimensional transition metal carbides/nitrides (MXenes) have shown great promise in various applications. However, mass production of MXenes suffers from the excessive use of toxic fluorine-containing reagents. Herein, a new method was validated for synthesizing MXenes from five MAX ceramics. The method features a minimized (stoichiometric) dosage of F-containing reagent (NaBF4) and polyols (glycerol, erythritol, and xylitol) as the reaction solvent. Due to the sweetness of polyols and the low environmental impact, we refer to this method as a "sweet" synthesis of MXenes. An in-depth molecular dynamics simulation study, combined with experimental kinetic parameters, further revealed that the diffusion of F- in the confined interplanar space is rate-determining for the etching reaction. The expansion of interlayer spacing by polyols effectively reduces the diffusion activation energy of F- and accelerates the etching reaction.

7.
Nano Lett ; 24(34): 10458-10466, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39146031

RESUMO

Rechargeable magnesium batteries (rMBs) are promising candidates for next-generation batteries in which sulfides are widely used as cathode materials. The slow kinetics, low redox reversibility, and poor magnesium storage stability induced by the large Coulombic resistance and ionic polarization of Mg2+ ions have obstructed the development of high-performance rMBs. Herein, a Cu1.8S1-xSex cathode material with a two-dimensional sheet structure has been prepared by an anion-tuning strategy, achieving improved magnesium storage capacity and cycling stability. Element-specific synchrotron radiation analysis is evidence that selenium incorporation has indeed changed the chemical state of Cu species. Density functional theory calculations combined with kinetics analysis reveal that the anionic substitution endows the Cu1.8S1-xSex electrode with favorable charge-transfer kinetics and low ion diffusion barrier. The principal magnesium storage mechanisms and structural evolution process have been revealed in details based on a series of ex situ investigations. Our findings provide an effective heteroatom-tuning tactic of optimizing electrode structure toward advanced energy storage devices.

8.
Nano Lett ; 24(29): 8866-8871, 2024 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-38976330

RESUMO

Access to intrinsic properties of a 2D material is challenging due to the absence of a bulk that would dominate over surface contamination, and this lack of bulk also precludes effective conventional cleaning methods that are almost always sacrificial. Suspended graphene and carbon contaminants represent the most salient challenge. This work has achieved ultraclean graphene, attested by electron energy loss (EEL) spectra unprecedentedly exhibiting fine-structure features expected from bonding and band structure. In the cleaning process in a transmission electron microscope, radicals generated by radiolysis of intentionally adsorbed water remove organic contaminants, which would otherwise be feedstock of the notorious electron irradiation induced carbon deposition. This method can be readily adapted to other experimental settings and other materials to enable previously inhibited undertakings that rely on the intrinsic properties or ultimate thinness of 2D materials. Importantly, the method is surprisingly simple and robust, easily implementable with common lab equipment.

9.
J Biol Chem ; 299(7): 104853, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37220854

RESUMO

We have investigated the equilibrium properties and rapid-reaction kinetics of the isolated butyryl-CoA dehydrogenase (bcd) component of the electron-bifurcating crotonyl-CoA-dependent NADH:ferredoxin oxidoreductase (EtfAB-bcd) from Megasphaera elsdenii. We find that a neutral FADH• semiquinone accumulates transiently during both reduction with sodium dithionite and with NADH in the presence of catalytic concentrations of EtfAB. In both cases full reduction of bcd to the hydroquinone is eventually observed, but the accumulation of FADH• indicates that a substantial portion of reduction occurs in sequential one-electron processes rather than a single two-electron event. In rapid-reaction experiments following the reaction of reduced bcd with crotonyl-CoA and oxidized bcd with butyryl-CoA, long-wavelength-absorbing intermediates are observed that are assigned to bcdred:crotonyl-CoA and bcdox:butyryl-CoA charge-transfer complexes, demonstrating their kinetic competence in the course of the reaction. In the presence of crotonyl-CoA there is an accumulation of semiquinone that is unequivocally the anionic FAD•- rather than the neutral FADH• seen in the absence of substrate, indicating that binding of substrate/product results in ionization of the bcd semiquinone. In addition to fully characterizing the rapid-reaction kinetics of both the oxidative and reductive half-reactions, our results demonstrate that one-electron processes play an important role in the reduction of bcd in EtfAB-bcd.


Assuntos
Butiril-CoA Desidrogenase , Megasphaera elsdenii , Oxirredutases , Butiril-CoA Desidrogenase/química , Butiril-CoA Desidrogenase/metabolismo , Elétrons , Ferredoxinas/metabolismo , Cinética , Megasphaera elsdenii/enzimologia , NAD/metabolismo , Oxirredução , Oxirredutases/química , Oxirredutases/metabolismo , Espectroscopia de Ressonância de Spin Eletrônica , Estrutura Terciária de Proteína , Modelos Moleculares
10.
Small ; 20(14): e2308881, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37984861

RESUMO

Organic electrodes that embrace multiple electron transfer and efficient redox reactions are desirable for green energy storage batteries. Here, a novel organic electrode material is synthesized, i.e., 2, 2'-((disulfanediylbis (4, 1-phenylene)) bis(azanediyl)) bis (naphthalene-1, 4-dione) (MNQ), through a simple click reaction between common carbonyl and organosulfur compounds and demonstrate its application potential as a high-performance cathode material in rechargeable lithium batteries. MNQ exhibits the aggregation effect of redox-active functional groups, the advantage of fast reaction kinetics from molecular structure evolution, and the decreased solubility in aprotic electrolytes resulting from intermolecular interactions. As expected, the MNQ electrode exhibits a high initial discharge capacity of 281.2 mA h g-1 at 0.5 C, equivalent to 97.9% of its theoretical capacity, and sustains stable long-term cycling performance of over 1000 cycles at 1 C. This work adds a new member to the family of organic electrode materials, providing performance-efficient organic molecules for the design of rechargeable battery systems, which will undoubtedly spark great interest in their applications.

11.
Small ; 20(21): e2310577, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38279633

RESUMO

Bridging functionalities in periodic mesoporous organosilicas (PMOs) enable new functionalities for a wide range of applications. Bridge cleavage is frequently observed during anneals required to form porous structures, yet the mechanism of these bridge cleavages has not been completely resolved. Here, these chemical transformations and their kinetic pathways on sub-millisecond timescales induced by laser heating are revealed. By varying anneal times and temperatures, the transformation dynamics of bridge cleavage and structural transformations and their activation energies are determined. The structural relaxation time for individual reactions and their effective local heating time are determined and compared, and the results directly demonstrate the manipulation of different molecules through kinetic control of the sequence of reactions. By isolating and understanding the earliest stage of structural transformations, this study identifies the kinetic principles for new synthesis and post-processing routes to control individual molecules and reactions in PMOs and other material systems with multi-functionalities.

12.
Small ; : e2405141, 2024 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-39194403

RESUMO

Lithium-sulfur batteries (LSBs) have the advantages of high theoretical specific capacity, excellent energy density, abundant elemental sulfur reserves. However, the LSBs is mainly limited by shuttling of lithium polysulfides (LiPSs), slow reaction kinetics of sulfur cathode. For solving the above problems, by developing high-performance battery separators, the reversible capacity, Coulombic efficiency (CE) and cycle life of LSBs can be effectively enhanced. Carbon-free based metal compounds are expected to be highly efficient separator modifiers for a new generation of high-performance LSBs by virtue of superior chemical adsorption capacity, strong catalytic properties and excellent lithophilicity to a certain extent. They can give play to the synergistic effect of their "adsorption-catalysis" sites to accelerate the redox kinetics of LiPSs, and their good lithophilicity can accelerate the Li+ transport kinetics, thus showing more remarkable electrochemical performances. However, a comprehensive summary of carbon-free metal compounds-modified separators for LSBs is still lacking. Here, this review systematically summarizes the researching progresses and performance characteristics of carbon-free-based metal compounds modified materials for separators of LSBs, and summarizes the corresponding mechanisms of using carbon-based separators to enhance the performance of LSBs. Finally, the review also looks forward to the prospects of LSBs using carbon-free metal compounds separators.

13.
Small ; 20(34): e2401481, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38616774

RESUMO

Organic cathode materials show excellent prospects for sodium-ion batteries (SIBs) owing to their high theoretical capacity. However, the high solubility and low electrical conductivity of organic compounds result in inferior cycle stability and rate performance. Herein, an extended conjugated organic small molecule is reported that combines electroactive quinone with piperazine by the structural designability of organic materials, 2,3,7,8-tetraamino-5,10-dihydrophenazine-1,4,6,9-tetraone (TDT). Through intermolecular condensation reaction, many redox-active groups C═O and extended conjugated structures are introduced without sacrificing the specific capacity, which ensures the high capacity of the electrode and enhances rate performance. The abundant NH2 groups can form intermolecular hydrogen bonds with the C═O groups to enhance the intermolecular interactions, resulting in lower solubility and higher stability. The TDT cathode delivers a high initial capacity of 293 mAh g-1 at 500 mA g-1 and maintains 90 mAh g-1 at an extremely high current density of 70 A g-1. The TDT || Na-intercalated hard carbon (Na-HC) full cells provide an average capacity of 210 mAh g-1 during 100 cycles at 500 mA g-1 and deliver a capacity of 120 mAh g-1 at 8 A g-1.

14.
Small ; 20(38): e2402466, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38742945

RESUMO

Aqueous Zinc-sulfur (Zn-S) batteries are promising for the field of energy storage due to their low cost, high theoretical capacity, and safety. However, the large volume expansion and the inherently poor conductivity of sulfur would result in electrode cracking and sluggish reaction kinetics, limiting the practical application of Zn-S batteries. Herein, commercial zinc sulfide (ZnS) is employed instead of S as cathode and proposed a doping modification strategy to solve the above problems. The designed ZnS0.93Se0.07 cathode shows good cycle stability and much-improved reaction kinetics, which is due to the smaller bandgap of ZnS0.93Se0.07 (1.40 eV) compared to ZnS (1.86 eV). As a result, the obtained ZnS0.93Se0.07 cathode exhibits a high specific capacity of 552 mAh g-1 (1672.6 mAh g-1 based on S) at 0.1 A g-1 and 330 mAh g-1 (1000 mAh g-1 based on S) at 2 A g-1. Moreover, the ZnS0.93Se0.07 cathode can provide a high areal capacity of 3.8 mAh cm-2 at a high mass loading of 10 mg cm-2 and limited electrolyte (4 µL mg-1). This work provides a simple and effective cathode modification strategy, which is conducive to promoting the practical application of Zn-S batteries.

15.
Small ; : e2404171, 2024 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-39185810

RESUMO

All-solid-state lithium sulfide-based batteries (ASSLSBs) have drawn much attention due to their intrinsic safety and excellent performance in overcoming the polysulfide shuttle effect. However, the sluggish kinetics of Li2S cathode severely impede commercial utilization. Here, a Cu+, I- co-doping strategy is employed to activate the kinetics of Li2S to construct high-performance ASSLSBs. The electronic conductivity and Li-ion diffusion coefficient of the co-doped Li2S are increased by five and two orders of magnitude, respectively. Cu+ as a redox medium greatly improves the reaction kinetics, which is supported by ex situ X-ray photoelectron spectroscopy. Density functional theory calculation (DFT) shows that Cu+, I- co-doping reduces the Li-ions diffusion energy barrier. The co-doped Li2S exhibits a remarkable improvement in capacity (1165.23 mAh g-1 (6.65 times that of pristine Li2S) at 0.02 C and 592.75 mAh g-1 at 2 C), and excellent cycling stability (84.58% capacity retention after 6200 cycles at 2 C) at room temperature. Moreover, an ASSLSB, fabricated with a lithium-free (Si─C) anode, obtains a high specific capacity of 1082.7 mAh g-1 at 0.05 C and 97% capacity retention after 400 cycles at 0.5 C. This work provides a broad prospect for the development of ASSLSBs with practical energy density exceeding that of traditional lithium-ion batteries.

16.
Small ; : e2402811, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38845061

RESUMO

In this study, a novel approach is introduced to address the challenges associated with structural instability and sluggish reaction kinetics of δ-MnO2 in aqueous zinc ion batteries. By leveraging zwitterionic betaine (Bet) for intercalation, a departure from traditional cation intercalation methods, Bet-intercalated MnO2 (MnO2-Bet) is synthesized. The positively charged quaternary ammonium groups in Bet form strong electrostatic interactions with the negatively charged oxygen atoms in the δ-MnO2 layers, enhancing structural stability and preventing layer collapse. Concurrently, the negatively charged carboxylate groups in Bet facilitate the rapid diffusion of H+/Zn2+ ions through their interactions, thus improving reaction kinetics. The resulting MnO2-Bet cathode demonstrates high specific capacity, excellent rate capability, fast reaction kinetics, and extended cycle life. This dual-function intercalation strategy significantly optimizes the electrochemical performance of δ-MnO2, establishing it as a promising cathode material for advanced aqueous zinc ion batteries.

17.
Small ; 20(1): e2304806, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37649194

RESUMO

The sluggish kinetics in Ni-rich cathodes at subzero temperatures causes decreased specific capacity and poor rate capability, resulting in slow and unstable charge storage. So far, the driving force of this phenomenon remains a mystery. Herein, with the help of in-situ X-ray diffraction and time of flight secondary ion mass spectrometry techniques, the continuous accumulation of both the cathode electrolyte interphase (CEI) film formation and the incomplete structure evolution during cycling under subzero temperature are proposed. It is presented that excessively uniform and thick CEI film generated at subzero temperatures would block the diffusion of Li+ -ions, resulting in incomplete phase evolution and clear charge potential delay. The incomplete phase evolution throughout the Li+ -ion intercalation/de-intercalation processes would further cause low depth of discharge and poor electrochemical reversibility with low initial Coulombic efficiency, as well. In addition, the formation of the thick and uniform CEI film would also consume Li+ -ions during the charging process. This discovery highlights the effects of the CEI film formation behavior and incomplete phase evolution in restricting electrochemical kinetics under subzero temperatures, which the authors believe would promote the further application of the Ni-rich cathodes.

18.
Small ; 20(10): e2304846, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37910867

RESUMO

Fast recombination dynamics of photocarriers competing with sluggish surface photohole oxidation kinetics severely restricts the photoelectrochemical (PEC) conversion efficiency of photoanode. Here, a defect engineering strategy is developed to regulate photohole transfer and interfacial injection dynamics of 2D ZnIn2 S4 (ZIS). Via selectively introducing substitutional Cd dopant at Zn sites of the ZIS basal plane, energy band structure and surface electrochemical activity are successfully modulated in the Cd-doped ZIS (Cd-ZIS) nanosheet array photoanode. Comprehensive characterizations manifest that a shallow acceptor level induced by Cd doping and superior electrochemical activity make surface Cd dopants simultaneously act as capture centers and active sites to mediate photohole dynamics at the reaction interface. In depth photocarrier dynamics analysis demonstrates that highly efficient photohole capture of Cd dopants brings about effective space separation of photocarriers and acceleration of surface reaction kinetics. Therefore, the optimum 2D Cd-ZIS achieves excellent PEC solar energy conversion efficiency with a photocurrent density of 5.1 mA cm-2 at 1.23 VRHE and a record of applied bias photon-to-current efficiency (ABPE) of 3.0%. This work sheds light on a microstructure design strategy to effectively regulate photohole dynamics for the next-generation semiconducting PEC photoanodes.

19.
Small ; : e2406165, 2024 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-39126365

RESUMO

The calcium looping technology employing CaO-based sorbents is pivotal for capturing CO2 from flue gas. However, the intrinsic low thermodynamic stability of CaO-based sorbents and the requisite molding step induce severe sintering issues, diminishing their cyclic stability. Herein, a high-entropy fluorite oxide (HEFO) inert stabilizer premised on entropy stabilization and synergistic effect strategies is introduced. HEFO-modified, CaO-based sorbent pellets are synthesized via a rapid cigarette butt-assisted combustion process (15 min) combined with the graphite molding method. Post-multiple cycles, their CO2 capture capacity reaches 0.373 g g-1, which is 2.6-fold superior to that of pure CaO, demonstrating markedly enhanced anti-sintering properties. First, the subtle morphological and crystallographic modifications suggest that the inherent entropy stability of HEFO imparts robust thermal resistance. Concurrently, the disordered structure of single-phase HEFO exhibits a high affinity for CaO, resulting in an interface binding energy of -1.83 eV, in sharp contrast to the -0.112 eV of pure CaO, thereby restricting CaO migration. Additionally, the multi-element synergistic effect of HEFO reduces the energy barrier by 0.15 eV, leading to a 40% and 140% increase in carbonation and calcination rates, respectively. This work presents highly efficient and rapidly synthesized CaO-based sorbent pellets, showcasing promising potential for industrial application.

20.
Small ; : e2403050, 2024 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-38984752

RESUMO

Applications of aqueous zinc ion batteries (ZIBs) for grid-scale energy storage are hindered by the lacking of stable cathodes with large capacity and fast redox kinetics. Herein, the intercalation of tetramethylammonium (TMA+) cations is reported into MoS2 interlayers to expand its spacing from 0.63 to 1.06 nm. The pre-intercalation of TMA+ induces phase transition of MoS2 from 2H to 1T phase, contributing to an enhanced conductivity and better wettability. Besides, The calculation from density functional theory indicates that those TMA+ can effectively shield the interactions between Zn2+ and MoS2 layers. Consequently, two orders magnitude high Zn2+ ions diffusion coefficient and 11 times enhancement in specific capacity (212.4 vs 18.9 mAh g‒1 at 0.1 A g‒1) are achieved. The electrochemical investigations reveal both Zn2+ and H+ can be reversibly co-inserted into the MoS2-TMA electrode. Moreover, the steady habitat of TMA+ between MoS2 interlayers affords the MoS2-TMA with remarkable cycling stability (90.1% capacity retention after 2000 cycles at 5.0 A g‒1). These performances are superior to most of the recent zinc ion batteries assembled with MoS2 or VS2-based cathodes. This work offers a new avenue to tuning the structure of MoS2 for aqueous ZIBs.

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