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1.
Emerg Infect Dis ; 30(1): 187-189, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-38147505

RESUMEN

We report a case of Spiroplasma bloodstream infection in a patient in China who developed pulmonary infection, acute respiratory distress syndrome, sepsis, and septic shock after emergency surgery for type A aortic dissection. One organism closely related to Spiroplasma eriocheiris was isolated from blood culture and identified by whole-genome sequencing.


Asunto(s)
Sepsis , Spiroplasma , Humanos , Spiroplasma/genética , China/epidemiología , Sepsis/diagnóstico , Sepsis/etiología
2.
Inorg Chem ; 63(41): 19322-19331, 2024 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-39361814

RESUMEN

Exploring high-performance and low-platinum-based electrocatalysts to accelerate the oxygen reduction reaction (ORR) at the air cathode of zinc-air batteries remains crucial. Herein, by combining electroless deposition and carbothermal reduction, a nitrogen-doped carbon-supported highly dispersed PtSn alloy nanocatalyst (PtSn/NC) was prepared for a high-efficiency ORR process. Electrochemical measurements show that PtSn/NC exhibits excellent electrocatalytic ORR activity with a half-wave potential of 0.850 V versus reversible hydrogen electrode (RHE), which is higher than that of commercial Pt/C (0.815 V). The PtSn/NC-based (20 µgPt cm-2) rechargeable Zn-air battery exhibited astonishing performance with a maximum power density of up to 150.1 mW cm-2, as well as excellent rate performance and charge/discharge stability. Physical characterization reveals that carbothermal reduction could compel the transformation of Sn oxide into metallic Sn, which then alloys with the deposited Pt atoms to form the PtSn nanoalloy, in which electrons are transferred from Sn atoms to neighboring Pt atoms, thereby improving the ability of Pt-based active sites to catalyze the ORR process in PtSn/NC by optimizing the unoccupied d-band of Pt atoms. This work provides a reliable and innovative route for the rational design of highly dispersed Pt-based alloy ORR electrocatalysts.

3.
Angew Chem Int Ed Engl ; 62(32): e202302746, 2023 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-37300514

RESUMEN

Lewis-base sites have been widely applied to regulate the properties of Lewis-acid sites in electrocatalysts for achieving a drastic technological leap of lithium-oxygen batteries (LOBs). Whereas, the direct role and underlying mechanism of Lewis-base in the chemistry for LOBs are still rarely elucidated. Herein, we comprehensively shed light on the pivotal mechanism of Lewis-base sites in promoting the electrocatalytic reaction processes of LOBs by constructing the metal-organic framework containing Lewis-base sites (named as UIO-66-NH2 ). The density functional theory (DFT) calculations demonstrate the Lewis-base sites can act as electron donors that boost the activation of O2 /Li2 O2 during the discharged-charged process, resulting in the accelerated reaction kinetics of LOBs. More importantly, the in situ Fourier transform infrared spectra and DFT calculations firstly demonstrate the Lewis-base sites can convert Li2 O2 growth mechanism from surface-adsorption growth to solvation-mediated growth due to the capture of Li+ by Lewis-base sites upon discharged process, which weakens the adsorption energy of UIO-66-NH2 towards LiO2 . As a proof of concept, LOB based on UIO-66-NH2 can achieve a high discharge specific capacity (12 661 mAh g-1 ), low discharged-charged overpotential (0.87 V) and long cycling life (169 cycles). This work reveals the direct role of Lewis-base sites, which can guide the design of electrocatalysts featuring Lewis-acid/base dual centers for LOBs.

4.
Small ; 18(14): e2107250, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35166038

RESUMEN

Particulate matter (PM) pollution has become a serious environmental concern. Nanofibrous filters are widely reported to remove PM from polluted air. Herein, efficient and lightweight PM air filters are presented using airflow synergistic needleless electrospinning composed of auxiliary fields such as an airflow field and a secondary inductive electric field. Compared to needleless electrospinning with other spinnerets, it significantly improves productivity, fiber diameter, and porosity of fibrous air filters. The instant noodle-like nanofiber structure can also be controlled by adjusting the airflow velocity. These air filters exhibit high (2.5 µm particulate matter) PM2.5 removal efficiency (99.9%) and high (0.3 µm particulate matter) PM0.3 removal efficiency (99.1%), low pressure drop (56 Pa for PM2.5 and 78 Pa for PM0.3 ), and large dust holding capacitance (the maximum value is 168 g m-2 for PM2.5 , while 102 g m-2 for PM0.3 ). Meanwhile, the proposed PM filters are also tested suitable and stable to other polluted air filtrations such as cigarette smoke and sawdust. The large-scale synthesis of such an attractive nanofiber structure presents the great potential of high-performance filtration/separation materials.


Asunto(s)
Filtros de Aire , Nanofibras , Filtración , Material Particulado , Porosidad
5.
J Clin Pharm Ther ; 47(3): 263-269, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-34397110

RESUMEN

WHAT IS KNOWN AND OBJECTIVE: Metformin has been suggested to confer anticancer efficacy. However, it remains uncertain whether additional use of metformin could improve survival of women with breast cancer. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the influence of metformin on survival outcome in women with breast cancer. METHODS: Relevant RCTs were obtained by search of PubMed, Embase and Cochrane's Library databases from inception to 15 May 2021. A random-effects model incorporating the potential publication bias was used to pool the results. RESULTS AND DISCUSSION: Five phase II RCTs including 396 non-diabetic women with breast cancer were included in the meta-analysis. Pooled results showed that additional use of metformin was not associated with improved progression-free survival (PFS, hazard ratio [HR]: 1.00, 95% confidence interval [CI]: 0.70 to 1.43, p = 0.98; I2  = 32%) or overall survival (OS, HR: 1.00, 95% CI: 0.71 to 1.39, p = 0.98; I2  = 0%). Sensitivity analysis by excluding one study at a time showed consistent results (HR for PFS: 0.91 to 1.14, p all >0.05; HR for OS: 0.88 to 1.21, P all >0.05). WHAT IS NEW AND CONCLUSION: Current evidence from phase II clinical trials does not support that additional use of metformin could improve the survival outcome in women with breast cancer.


Asunto(s)
Neoplasias de la Mama , Metformina , Neoplasias de la Mama/tratamiento farmacológico , Supervivencia sin Enfermedad , Femenino , Humanos , Metformina/uso terapéutico , Supervivencia sin Progresión , Ensayos Clínicos Controlados Aleatorios como Asunto
6.
Small ; 16(24): e2001812, 2020 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-32431080

RESUMEN

Albeit the effectiveness of surface oxygen vacancy in improving oxygen redox reactions in Li-O2 battery, the underpinning reason behind this improvement remains ambiguous. Herein, the concentration of oxygen vacancy in spinel NiCo2 O4 is first regulated via magnetron sputtering and its relationship with catalytic activity is comprehensively studied in Li-O2 battery based on experiment and density functional theory (DFT) calculation. The positive effect posed by oxygen vacancy originates from the up shifted antibond orbital relative to Fermi level (Ef ), which provides extra electronic state around Ef , eventually enhancing oxygen adsorption and charge transfer during oxygen redox reactions. However, with excessive oxygen vacancy, the negative effect emerges because the metal ions are mostly reduced to low valence based on the electrical neutral principle, which not only destabilizes the crystal structure but also weakens the ability to capture electrons from the antibond orbit of Li2 O2 , leading to poor catalytic activity for oxygen evolution reaction (OER).

7.
Nanotechnology ; 31(9): 095403, 2020 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-31726433

RESUMEN

Three-dimensional (3D) carbon aerogels with well-defined structures, e.g. high specific surface area (SSA), appropriate pore size distribution, good electrical conductivity and ideal building blocks, have been regarded as promising electrode materials or substrates for incorporation with pseudocapacitive materials for energy storage and conversion applications. Herein, we report a simple and scalable sonochemical method followed by a chemical activation process to transform bacterial cellulose-derived carbon nanofiber aerogels (CNFAs) into 3D graphene nanoribbon aerogels (GNRAs) for supercapacitors. Benefiting from a high SSA, reasonable pore size distribution and good conductivity, the GNRA electrode demonstrates a long cyclability, good rate capability and high charge storage performance for supercapacitors, yielding more than 1.5 times (three-electrode cell) and 2.6 times (two-electrode cell) the gravimetric capacitance of the CNFA electrode. In addition, a hybrid Ni-Co layered double hydroxides (LDHs)@GNRAs electrode achieves an impressive gravimetric capacitance of 968 F g-1 (based on the mass of the active material) at a current density of 1 A g-1. Moreover, an asymmetric supercapacitor device with a remarkable energy density of 29.87 Wh kg-1, wide working voltage windows of 1.6 V and good cycling stability (63.5% retention after 10 000 cycles) is achieved by using the GNRA as an anode and the Ni-Co LDHs@GNRAs as a cathode.

8.
Small ; 15(6): e1804701, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30632277

RESUMEN

High-performance flexible lithium-oxygen (Li-O2 ) batteries with excellent safety and stability are urgently required due to the rapid development of flexible and wearable devices. Herein, based on an integrated solid-state design by taking advantage of component-interaction between poly(vinylidene fluoride-co-hexafluoropropylene) and nanofumed silica in polymer matrix, a stable quasi-solid-state electrolyte (PS-QSE) for the Li-O2 battery is proposed. The as-assembled Li-O2 battery containing the PS-QSE exhibits effectively improved anodic reversibility (over 200 cycles, 850 h) and cycling stability of the battery (89 cycles, nearly 900 h). The improvement is attributed to the stability of the PS-QSE (including electrochemical, chemical, and mechanical stability), as well as the effective protection of lithium anode from aggressive soluble intermediates generated in cathode. Furthermore, it is demonstrated that the interaction among the components plays a pivotal role in modulating the Li-ion conducting mechanism in the as-prepared PS-QSE. Moreover, the pouch-type PS-QSE based Li-O2 battery also shows wonderful flexibility, tolerating various deformations thanks to its integrated solid-state design. Furthermore, holes can be punched through the Li-O2 battery, and it can even be cut into any desired shape, demonstrating exceptional safety. Thus, this type of battery has the potential to meet the demands of tailorability and comformability in flexible and wearable electronics.

9.
Luminescence ; 32(6): 913-917, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28185413

RESUMEN

Sr4 Al2 O7 :Eu3+ and Sr4 Al2 O7 :Dy3+ phosphors with alkali metal substitution were prepared using a sol-gel method. The effects of a charge compensator R on the structure and luminescence of Sr4 Al2 O7 :Re3+ ,R+ (Re = Eu and Dy; R = Li, Na and K) phosphors were investigated in detail. Upon heating to 1400°C, the structure of the prepared samples was that of the standard phase of Sr4 Al2 O7 . Under ultraviolet excitation, all Sr4 Al2 O7 :Eu3+ ,R+ samples exhibited several narrow emission peaks ranging from 550 to 700 nm due to the 4f â†’ 4f transition of Eu3+ ions. All Sr4 Al2 O7 :Dy3+ ,R+ phosphors showed two emission peaks at 492 and 582 nm, due to the 4 F9/2  â†’ 6 H15/2 and 4 F9/2  â†’ 6 H13/2 transitions of Dy3+ ions, respectively. The luminescence intensity of Sr4 Al2 O7 :Re3+ ,R+ (Re = Eu and Dy; R = Li, Na and K) phosphors improved markedly upon the addition of charge compensators, promoting their application in white light-emitting diodes with a near-ultraviolet chip.


Asunto(s)
Litio/química , Sustancias Luminiscentes/síntesis química , Potasio/química , Sodio/química , Europio , Luminiscencia , Sustancias Luminiscentes/química
10.
Luminescence ; 32(1): 119-124, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27216747

RESUMEN

Eu2+ -doped Sr2 SiO4 phosphor with Ca2+ /Zn2+ substitution, (Sr1-x Mx )2 SiO4 :Eu2+ (M = Ca, Zn), was prepared using a high-temperature solid-state reaction method. The structure and luminescence properties of Ca2+ /Zn2+ partially substituted Sr2 SiO4 :Eu2+ phosphors were investigated in detail. With Ca2+ or Zn2+ added to the silicate host, the crystal phase could be transformed between the α-form and the ß-form of the Sr2 SiO4 structure. Under UV excitation at 367 nm, all samples exhibit a broad band emission from 420 to 680 nm due to the 4f6 5d1  â†’ 4f7 transition of Eu2+ ions. The broad emission band consists of two peaks at 482 and 547 nm, which correspond to Eu2+ ions occupying the ten-fold oxygen-coordinated Sr.(I) site and the nine-fold oxygen-coordinated Sr.(II) site, respectively. The luminescence properties, including the intensity and lifetime of Sr2 SiO4 :Eu2+ phosphors, improved remarkably on Ca2+ /Zn2+ addition, and promote its application in white light-emitting diodes. Copyright © 2016 John Wiley & Sons, Ltd.


Asunto(s)
Calcio/química , Europio/química , Luz , Silicatos/química , Estroncio/química , Zinc/química , Luminiscencia
11.
Luminescence ; 30(5): 533-7, 2015 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-25223510

RESUMEN

Eu(3+)-doped calcium titanate red phosphors, Ca(1-x)Znx TiO3:Eu(3+), were prepared by the sol-gel method. The structure of prepared Ca(1-x)Znx TiO3:Eu(3+) phosphors were investigated by X-ray diffraction and infrared spectra. Due to the (5) D0 → (7) F1-3 electron transitions of Eu(3+) ions, photoluminescence spectra showed a red emission at about 619 nm under excitation of 397 nm and 465 nm, respectively. When zinc was added to the host, the luminescent intensity of Ca(1-x)ZnxTiO3:Eu(3+) was markedly improved several fold compared with that of CaTiO3:Eu(3+). Ca0.9Zn0.1TiO3:Eu(3+) also had higher luminescence intensity than the commercially available Y2 O3:Eu(3+) phosphors under UV light excitation.


Asunto(s)
Calcio/química , Europio/química , Sustancias Luminiscentes/química , Zinc/química , Mediciones Luminiscentes , Microscopía Electrónica de Rastreo , Espectroscopía Infrarroja por Transformada de Fourier , Titanio/química , Rayos Ultravioleta
12.
Chem Commun (Camb) ; 60(73): 9962-9965, 2024 Sep 10.
Artículo en Inglés | MEDLINE | ID: mdl-39171778

RESUMEN

Functional composite layers composed of an amino-functionalized zirconium 1,4-dicarboxybenzene metal-organic framework were constructed on zinc anodes to mitigate the interface disturbances in aqueous batteries. These layers enable robust Zn2+ adsorption and homogenized Zn2+ transport and deposition kinetics, facilitating achieving high stability in a symmetric cell (3500 h) and a full cell (35 000 cycles, 96.7%).

13.
Chem Sci ; 15(30): 12108-12117, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39092122

RESUMEN

In situ polymerized 1,3-dioxolane (PDOL) is widely utilized to construct solid polymer electrolytes because of its high room-temperature ionic conductivity and good compatibility with lithium metal. However, the current polymerization additives used in PDOL do not effectively contribute to the formation of a robust solid electrolyte interphase (SEI), leading to decreased cycle life. Herein, a film-forming Lewis acid, tris(hexafluoroisopropyl) borate (THB), is demonstrated not only to be a catalyst for the ring-opening polymerization of DOL, but also an additive for the formation of a stable fluorine- and boron-rich SEI to improve the interfacial stability and suppress the Li dendrite growth. Moreover, molecular dynamics simulations and experimental results demonstrate that the introduction of THB can promote the dissociation of lithium salt and release more Li+ while the boron site can effectively restrict the free movement of TFSI- anion, thus increasing Li+ transference numbers (0.76) and ensuring the long-term cycling stability of cells. By using THB-PDOL, a stable cycling of Li‖Li symmetric cell for 600 h at a capacity of 0.5 mA h cm-2 can be achieved. Furthermore, employing THB-PDOL in Li‖LiFePO4 full cell enables a capacity retention of 98.64% after 300 cycles at 1C and a capacity retention of 95.39% after 200 cycles at a high temperature (60 °C). At the same time, this electrolyte is also suitable for the Li‖NCM523 full cell, which also achieves excellent stability of more than 180 cycles. This film-forming Lewis acid additive provides ideas for designing low-cost, high-performance PDOL-based lithium metal batteries.

14.
Nanoscale ; 16(16): 8096-8107, 2024 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-38566568

RESUMEN

Metal single-atom catalysts have attracted widespread attention in the field of lithium-oxygen batteries due to their unique active sites, high catalytic selectivity, and near total atomic utilization efficiency. Isolated metal atoms not only serve as the active sites themselves, but also function as modulators, reversely regulating the surface electronic structure of the support to enhance its inherent electrocatalytic activities. Despite the potential of isolated metal atom-driven active sites, understanding the structure-activity relationship remains a challenge. In this study, we present a ruthenium single-atom doping-driven cost-effective and durable tricobalt tetroxide electrocatalyst with excellent oxygen electrode electrocatalytic activity. The lithium-oxygen battery with this catalyst as the oxygen electrode demonstrates high performance, achieving a capacity of up to 25 000 mA h g-1 and maintaining good stability over 400 cycles at a current density of 100 mA g-1. This improvement is attributed to the exquisite control of the morphology and structure of the discharge product, lithium peroxide. The aresults of physical characterization and theoretical calculations reveal that isolated ruthenium atoms bond with the tetrahedral cobalt site, resulting in spin polarization enhancement and rearrangement of d orbital energy levels in cobalt. This rearrangement reduces the dz2 orbital occupancy and promotes their transfer to the octahedral cobalt site, thereby enhancing its adsorption capacity for the oxygen-containing intermediates, and ultimately increasing the electrocatalytic activity of the oxygen evolution reaction. This work presents an innovative strategy to regulate the catalytic activity of metal oxides by introducing another metal single atom.

15.
J Colloid Interface Sci ; 657: 384-392, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38056043

RESUMEN

Sculpting crystal configurations can vastly affect the charge and orbital states of electrocatalysts, fundamentally determining the catalytic activity of lithium-oxygen (Li-O2) batteries. However, the crucial role of crystal configurations in determining the electronic states has usually been neglected and needs to be further examined. Herein, we introduce orthorhombic and trigonal system into 0.5La0.6Sr0.4MnO3-0.5LaMn0.6Co0.4O3 (LSMCO) by selectively incorporating Sr and Co cations into the LaMnO3 framework during the sol-gel process, which is used to explore the relationship among crystal structure, electronic states and catalytic performance. Based on both experimental and theoretical calculations, the dual-crystal configurations induce strong lattice distortion, which promotes MnO6 octahedra vibration and shortened MnO bonds. Furthermore, the suppressed Jahn-Teller distortion weakens the orbital arrangement and accelerates the charge delocalization, leading to the conversion of Mn3+ to Mn4+ and optimized electronic states. Ultimately, this resulted in optimized Mn 3d and O 2p orbital hybridization and activated lattice oxygen function, leading to a significant improvement in electrocatalytic activity. The LSMCO catalyzed Li-O2 battery achieves enhanced discharge capacity of 14498.7 mAh/g and cycling stability of 258 cycles. This work highlights the significance of inner structure and presents a feasible strategy for engineering crystal configurations to boost electrocatalysis of Li-O2 batteries.

16.
J Colloid Interface Sci ; 650(Pt A): 257-265, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37406566

RESUMEN

Aqueous zinc ion hybrid capacitors (ZHCs) are promising as electrochemical energy storage devices due to their safety and cost-effectiveness. However, the practical application of aqueous ZHCs is impeded by zinc dendrite growth and side reactions induced by H2O during long-term cycling. Herein, an organic small molecule, dimethyl sulfoxide (DMSO), is elaborately introduced into 2 M ZnSO4 electrolyte to simultaneously overcome these challenges. As convincingly evidenced by experimental and theoretical results, the DMSO reconstructs the Zn[(H2O)6]2+ structure and original hydrogen bond networks at the molecular level. By forming coordination bonds with Zn2+ and hydrogen bonds with H2O due to the stronger electron donating ability of oxygen in molecule, DMSO establishes a Zn2+ solvation shell structure that inhibits H2O decomposition and dendrite growth. As a proof of concept, the implementation of this hybrid electrolyte in a Zn||Cu asymmetrical cell results in a high Coulombic efficiency (CE) of over 99.8% for 568 cycles at a current density of 2 mA cm-2. Furthermore, the full cells using this hybrid electrolyte coupled with activated carbon (AC) cathode can operate for over 30,000 cycles. These results suggest that reconstructing the solvation structure and hydrogen bond networks guide the design of electrolytes for the development of high-performance aqueous ZHCs.

17.
Nanoscale ; 15(37): 15318-15327, 2023 Sep 29.
Artículo en Inglés | MEDLINE | ID: mdl-37682066

RESUMEN

Minimizing the amount of metallic lithium (Li) to zero excess to achieve an anode-free configuration can help achieve safer, higher energy density, and more economical Li metal batteries. Nevertheless, removal of excess Li creates challenges for long-term cycling performance in Li metal batteries due to the lithiophobic copper foils as anodic current collectors. Here, we improve the long-term cycling performance of anode-free Li metal batteries by modifying the anode-free configuration. Specifically, a lithiophilic Au nanoparticle-anchored reduced graphene oxide (Au/rGO) film is used as an anodic modifier to reduce the Li nucleation overpotential and inhibit dendrite growth by forming a lithiophilic LixAu alloy and solid solution, which is convincingly evidenced by density functional theory calculations and experimentally. Meanwhile, the flexible rGO film can also act as a buffer layer to endure the volume expansion during repeated Li plating/stripping processes. In addition, the Au/rGO film promotes a homogeneous distribution of the electric field over the entire anodic surface, thus ensuring a uniform deposition of Li during the electrodeposition process, which is convincingly evidenced by finite element simulations. As expected, the Li||Au/rGO-Li half-cell shows a highly stable long-term cycling performance for at least 500 cycles at 0.5 mA cm-2 and 0.5 mA h cm-2. A Li2S-based anode-free full cell allows achieving a stable operation life of up to 200 cycles with a capacity retention of 63.3%. This work provides a simple and scalable fabrication method to achieve anode-free Li2S-based cells with high anodic interface stability and a long lifetime.

18.
Small Methods ; 7(1): e2201177, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36529700

RESUMEN

With markedly expansive demand in energy storage devices, rechargeable batteries will concentrate on achieving the high energy density and adequate security, especially under harsh operating conditions. Considering the high capacity (3860 mA h g-1 ) and low electrochemical potential (-3.04 V vs the standard hydrogen electrode), lithium metal is identified as one of the most promising anode materials, which has sparked a research boom. However, the intrinsically high reactivity triggers a repeating fracture/reconstruction process of the solid electrolyte interphase, side reactions with electrolyte and lithium dendrites, detrimental to the electrochemical performance of lithium metal batteries (LMBs). Even worse, when exposed to air, lithium metal will suffer severe atmospheric corrosion, especially the reaction with moisture, leading to grievous safety hazards. To settle these troubles, constructing air-stable protective layers (ASPLs) is an effective solution. In this review, besides the necessity of ASPLs is highlighted, the modified design criteria, focusing on enhancing chemical/mechanical stability and controlling ion flux, are proposed. Correspondingly, current research progress is comprehensively summarized and discussed. Finally, the perspectives of developing applicable lithium metal anodes (LMAs) are put forward. This review guides the direction for the practical use of LMAs, further pushing the evolution of safe and stable LMBs.

19.
J Colloid Interface Sci ; 635: 138-147, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36584614

RESUMEN

The electronic structure of cathode catalysts dominates the electrochemistry reaction kinetics in lithium-oxygen batteries. However, conventional catalysts perform inferior intrinsic activity due to the low d-band level of the active sites makes it difficult to bond with the reaction intermediates, which results in poor electrochemical performance of lithium-oxygen batteries. Herein, NiFe2O4/MoS2 heterostructures are elaborately constructed to reach an electronic state balance for the active sites, which realizes the upper shift of the d-band level and enhanced adsorption of intermediates. Density functional theory calculation suggests that the d-band center of Fe active sites on the heterostructure moves toward the Fermi level, demonstrating the heterointerface engineering endows Fe active sites with high d-band level by the transfer and balance of electron. As a proof of concept, lithium-oxygen battery catalyzed by NiFe2O4/MoS2 exhibits a large specific capacity of 21526 mA h g-1 and an extended cycle performance for 268 cycles. Moreover, NiFe2O4/MoS2 with strong adsorption to intermediates promotes the uniform growth of discharge products, which is favor of the reversible decomposition during cycling. This work presents the energy band regulation of the active sites in heterostructure catalysts has great feasibility for enhancing catalytic activities.

20.
J Colloid Interface Sci ; 652(Pt A): 727-736, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37453874

RESUMEN

Rechargeable aqueous zinc-ion hybrid supercapacitors (ZHSs) are drawing extensive attention because of their cost-effectiveness and diminished safety hazards. Nevertheless, large-scale application of ZHSs has been hindered by the severe side reactions and rampant dendrites growth on the surface of Zn metal anodes. Herein, we propose a three-dimensional organic-inorganic composite frame material as an artificial bi-functional layer coated on the zinc foil, featuring nitrogenous functional groups with zincophilicity (abbreviated as NCFM@Zn). The nitrogen (N) site's strong adsorption capacity and synergistic effect of the sub-nanopore size promote rapid desolvation of zinc ions and reduce side reactions, while also prolonging galvanized nucleation's Sand's time and allowing for even nucleation. Moreover, the uniform distribution of N on the layer results in homogeneous zinc ions flux and supports consistent zinc plating while inhibiting dendrites generation. As a result of this unique artificial bi-functional layer, symmetric Zn cells can survive 2500 h at 2.5 mA cm-2. High-areal-capacity zinc||activated carbon hybrid supercapacitors also demonstrate 20,000 cycles at high Coulombic efficiency, thus highlighting the utter convenience and potential of this strategy for modifying rechargeable metal hybrid supercapacitor surfaces.

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