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1.
Dalton Trans ; 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-39005112

RESUMEN

In this manuscript, a simple one-pot heat-up method has been used to prepare multi-component copper-tin-sulfur nanomaterials, including binary Cu1.94S, ternary Cu4SnS4, and Cu1.94S/Cu4SnS4 nanocrystals by varying the reaction temperature, reaction time, and the type of copper source. Post-synthetic ligand exchange (LE) has further been introduced to replace the long-chain ligands originating from 1-dodecanethiol. It has been found that the LE process not only changes the surface ligands but also significantly affects the crystal structure and optical properties of nanocrystals. After LE, the crystal structures of Cu1.94S and Cu4SnS4 transformed to Cu7S4 and Cu3SnS4, respectively, with the Cu1.94S/Cu4SnS4 nanocrystals showing the same trend. This phenomenon could be ascribed to the loss of Cu+ originating from the strong complexation of Cu+ and ammonia with the formation of [Cu(NH3)n]2+ ions under aerobic conditions. Proton nuclear magnetic resonance (1H NMR) has been used to characterize the ligands on the surface before and after LE, which further demonstrated that the -SH was replaced during LE. Meanwhile, the band gaps of the obtained nanocrystals after LE show an obvious shift in the near-infrared region due to the evolution of crystal structures. This study will provide useful guidance for the LE of nanocrystals and the application of copper-based sulfide nanomaterials in optoelectronics and other fields.

2.
Adv Mater ; 36(24): e2400245, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38377331

RESUMEN

The construction of high-quality carbon-based energy materials through biotechnology has always been an eager goal of the scientific community. Herein, juice vesicles bioreactors (JVBs) bio-technology based on hesperidium (e.g., pomelo, waxberry, oranges) is first reported for preparation of carbon-based composites with controllable components, adjustable morphologies, and sizes. JVBs serve as miniature reaction vessels that enable sophisticated confined chemical reactions to take place, ultimately resulting in the formations of complex carbon composites. The newly developed approach is highly versatile and can be compatible with a wide range of materials including metals, alloys, and metal compounds. The growth and self-assembly mechanisms of carbon composites via JVBs are explained. For illustration, NiCo alloy nanoparticles are successfully in situ implanted into pomelo vesicles crosslinked carbon (PCC) by JVBs, and their applications as sulfur/carbon cathodes for lithium-sulfur batteries are explored. The well-designed PCC/NiCo-S electrode exhibits superior high-rate properties and enhanced long-term stability. Synergistic reinforcement mechanisms on transportation of ions/electrons of interface reactions and catalytic conversion of lithium polysulfides arising from metal alloy and carbon architecture are proposed with the aid of DFT calculations. The research provides a novel biosynthetic route to rational design and fabrication of carbon composites for advanced energy storage.

3.
Adv Mater ; 35(46): e2307186, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37619540

RESUMEN

The delicate design of innovative and sophisticated fibers with vertical porous skeleton and eminent electrochemical activity to generate directional ionic pathways and good faradic charge accessibility is pivotal but challenging for realizing high-performance fiber-shaped supercapacitors (FSCs). Here, hierarchically ordered hybrid fiber combined vertical-aligned and conductive Ti3 C2 Tx MXene (VA-Ti3 C2 Tx ) with interstratified electroactive covalent organic frameworks LZU1 (COF-LZU1) by one-step microfluidic synthesis is developed. Due to the incorporation of vertical channels, abundant redox active sites and large accessible surface area throughout the electrode, the VA-Ti3 C2 Tx @COF-LZU1 fibers express exceptional gravimetric capacitance of 787 F g-1 in a three-electrode system. Additionally, the solid-state asymmetric FSCs deliver a prominent energy density of 27 Wh kg-1 , capacitance of 398 F g-1 and cycling life of 20 000 cycles. The key to high energy storage ability originates from the decreased ions adsorption energy and ameliorative charge density distribution in vertically aligned and active hybrid fiber, accelerating ions transportation/accommodation and interfacial electrons transfer. Benefiting from excellent electrochemical performance, the FSCs offer sufficient energy supply to power watches, flags, and digital display tubes as well as be integrated with sensors to detect pulse signals, which opens a promising route for architecting advanced fiber toward the carbon neutrality market beyond energy-storage technology.

4.
Materials (Basel) ; 16(13)2023 Jun 30.
Artículo en Inglés | MEDLINE | ID: mdl-37445056

RESUMEN

Two-dimensional Cu2FeSnS4 (CFTS) nanosheets with exposed high-energy facets (111) have been synthesized by a facile, scalable, and cost-effective one-pot heating process. The CFTS phase formation is confirmed by both X-ray diffraction and Raman spectroscopy. The formation mechanism of exposed high-energy facet CFTS growth is proposed and its electrochemical and photoelectrochemical properties are investigated in detail to reveal the origin of the anisotropic effect of the high-energy facets. Dye-sensitized solar cells (DSSC) achieve a favorable power conversion efficiency of 5.92% when employing CFTS thin film as a counter electrode, suggesting its potential as a cost-effective substitute for Pt in DSSCs.

5.
ACS Appl Mater Interfaces ; 15(22): 26910-26917, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37246367

RESUMEN

Graphdiyne (GDY) has realized significant achievements in lithium-ion batteries (LIBs) because of its unique π-conjugated skeleton with sp- and sp2-hybridized carbon atoms. Enriching the accessible surface areas and diffusion pathways of Li ions can realize more storage sites and rapid transport dynamics. Herein, three-dimensional porous hydrogen-substituted GDY (HsGDY) is developed for high-performance Li-ion storage. HsGDY, fabricated via a versatile interface-assisted synthesis strategy, exhibits a large specific surface area (667.9 m2 g-1), a hierarchical porous structure, and an expanded interlayer space, which accelerate Li-ion accessibility and lithiation/delithiation. Owing to this high π-conjugated, conductive, and porous framework, HsGDY exhibits a large reversible capacity (930 mA h g-1 after 100 cycles at 1 A g-1), superior cycle (720 mA h g-1 after 300 cycles at 1 A g-1), and rate (490 mA h g-1 at 5 A g-1) performances. Density functional theory calculations of the low diffusion barrier in the lamination and vertical directions further reveal the fast Li-ion transport kinetics of HsGDY. Additionally, a LiCoO2-HsGDY full cell is constructed, which exhibits a good practical charge/discharge capacity of 128 mA h g-1 and stable cycling behavior. This study highlights the advanced design of next-generation LIBs to sustainably develop the new energy industry.

6.
Angew Chem Int Ed Engl ; 61(44): e202212151, 2022 Nov 02.
Artículo en Inglés | MEDLINE | ID: mdl-36074042

RESUMEN

Flexible lithium sulfur batteries with high energy density and good mechanical flexibility are highly desirable. Here, we report a synergistic interface bonding enhancement strategy to construct flexible fiber-shaped composite cathodes, in which polypyrrole@sulfur (PPy@S) nanospheres are homogeneously implanted into the built-in cavity of self-assembled reduced graphene oxide fibers (rGOFs) by a facile microfluidic assembly method. In this architecture, sulfur nanospheres and lithium polysulfides are synergistically hosted by carbon and polymer interface, which work together to provide enhanced interface chemical bonding to endow the cathode with good adsorption ability, fast reaction kinetics, and excellent mechanical flexibility. Consequently, the PPy@S/rGOFs cathode shows enhanced electrochemical performance and high-rate capability. COMSOL Multiphysics simulations and density functional theory (DFT) calculations are conducted to elucidate the enhanced electrochemical performance. In addition, a flexible Li-S pouch cell is assembled and delivers a high areal capacity of 5.8 mAh cm-2 at 0.2 A g-1 . Our work offers a new strategy for preparation of advanced cathodes for flexible batteries.

7.
ACS Nano ; 16(7): 10130-10155, 2022 Jul 26.
Artículo en Inglés | MEDLINE | ID: mdl-35839097

RESUMEN

Fiber-based supercapacitors (F-SCs) have inspired widespread interest in the fields of wearable technology, energy, and carbon neutralization due to their highly deformable flexibility, fast charging/discharging capability, long-term stability, and energy conservation ability. In this review, we summarize the latest developments for fabricating fibrous electrodes of F-SCs where advanced micro two-dimensional (2D) building blocks (e.g., MXene and graphene) are chemically assembled and constructed into ordered mesofibers and multifunctional macrofabrics. Diverse fundamental principles of 2D hybrid nanosheets with respect to surface controls, pseudocapacitive modifications, and microstructural manipulations, promoting rapid electron transfer and charge conduction, are introduced. Additionally, various spinning methods for assembling and fabricating sophisticated fibers with advanced nano/microstructures, including hierarchical skeletons, anisotropic backbones, surface/entire porous frameworks, and vertical-aligned networks, for boosting ionic kinetic transport/storage are presented. Likewise, the structure-activity relationships between the porous structure and electrochemical performance are clarified. Moreover, multifunctional fabrics in terms of high flexibilities/strengths, superior electrical conductivities, and stabilized operations, which realize large energy density, deformable capability, and robust stability under harsh conditions, are emphasized. In particular, the potential power-supply applications, including flexible electronic devices, self-powered functions, and energy-sensor systems, are highlighted. Finally, a short conclusion and outlook, along with the current challenges and future opportunities of next-generation F-SCs, are proposed.

8.
Adv Mater ; 34(26): e2110511, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35259283

RESUMEN

High-entropy (HE) electrocatalysts are becoming a research hotspot due to their interesting "cocktail effect" and have great potential for tailored catalytic properties. However, it is still a great challenge to illustrate their inherent catalytic mechanism for the "cocktail effect", and there is also a paucity of quantitative descriptors to characterize the specific catalytic activity and give logical design strategies for HE systems. Herein, the unexpected activation of all metal sites in HE Cu-Co-Fe-Ag-Mo (oxy)hydroxides for the oxygen evolution reaction (OER) is reported, and it is found that metal-oxygen d-p hybridization, as an effective descriptor, can indicate the intrinsic activity of each metal site. According to the quantitative hybridization, introducing an electron donor (e.g., Ag) is raised and verified to reinforce the electrocatalytic activity of the HE system. Consequently, Ag-decorated Co-Cu-Fe-Ag-Mo (oxy)hydroxide (Ag@CoCuFeAgMoOOH) electrocatalysts are constructed by an electrochemical reconstruction method, and their OER performances are thoroughly characterized. The Ag@CoCuFeAgMoOOH is verified with a low overpotential (270 mV at 100 mA cm-2 ) and a small Tafel slope (35.3 mV dec-1 ), as well as good electrochemical stability. The favorable activity of the electron donor and underlying synergistic "cocktail effect" are demonstrated and disclosed. This work opens up a new strategy to guide the design/fabrication of advanced HE electrocatalysts.

9.
Nanotechnology ; 33(29)2022 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-33780917

RESUMEN

In the present study, a novel Cu4SnS4/reduced graphene oxide (CTS/rGO) composite was successfully prepared using a simple one-pot heat-up method. Post-synthetic ligand exchange (LE) and annealing process were performed to further increase the dispersibility and the conductivity of the prepared composite. An unexpected phase transformation from CTS to Cu3SnS4with an enhanced absorption in the near-infrared (NIR) region were observed after LE. Furthermore, the photodegradation of Rhodamine B (RhB) by the CTS/rGO composite was investigated. The CTS nanoplates with 10 wt% rGO treated through LE (CTS-10%rGO-LE) exhibited the highest (99.92%) degradation rate of RhB after 90 min of visible-light irradiation, which is approximately 10 and 1.28 times that of the pure CTS and the CTS-10%rGO treated using annealing (CTS-10%rGO-A). The enhancement of the photodegradation activity could be ascribed to the in-suit growth of CTS on rGO and the subsequent LE treatment, which effectively reduced the agglomeration of CTS and increased the electron-transfer ability of the composite materials. The CTS/rGO composite also exhibited high chemical stability of the photodegradation of RhB after four recycles. The electron paramagnetic resonance spectra reveal that ·OH and h+are the main active species in the photocatalytic degradation of RhB with CTS-LE and CTS-10%rGO-LE photocatalysts. The in-suit growth of the CTS/rGO composite with a subsequent LE treatment has the potential to serve as an efficient photocatalysts for the degradation of organic pollutants.

10.
Angew Chem Int Ed Engl ; 61(8): e202115559, 2022 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-34919307

RESUMEN

We report hierarchical-ordered ZIF-L(Zn)@Ti3 C2 Tx MXene core-sheath fibers, in which a ZIF-L(Zn) nanowall array sheath is grown vertically on an anisotropic Ti3 C2 Tx core by Ti-O-Zn/Ti-F-Zn chemical bonds. Through highly efficient microfluidic assembly and microchannel reactions, ZIF-L(Zn)@Ti3 C2 Tx exhibits well-developed micro-/mesoporosity, ordered ionic pathways, fast interfacial electron conduction and large-scale fabrication, significantly boosting charges dynamic transport and intercalation. The resultant ZIF-L(Zn)@Ti3 C2 Tx fiber presents large capacitance (1700 F cm-3 ) and outstanding rate performance in a 1 M H2 SO4 electrolyte. Additionally, ZIF-L(Zn)@Ti3 C2 Tx fiber-based solid-state asymmetric supercapacitors deliver high energy density (19.0 mWh cm-3 ), excellent capacitance (854 F cm-3 ), large deformable/wearable capabilities and long-time cyclic stability (20 000 cycles), which realize natural sunlight-induced self-powered applications to drive water level/earthquake alarm devices.

11.
Angew Chem Int Ed Engl ; 60(37): 20511-20517, 2021 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-34272927

RESUMEN

Developing self-oscillating soft actuators that enable autonomous, continuous, and directional locomotion is significant in biomimetic soft robotics fields, but remains great challenging. Here, an untethered soft photoactuators based on covalently-bridged black phosphorus-carbon nanotubes heterostructure with self-oscillation and phototactic locomotion under constant light irradiation is designed. Owing to the good photothermal effect of black phosphorus heterostructure and thermal deformation of the actuator components, the new actuator assembled by heterostructured black phosphorus, polymer and paper produces light-driven reversible deformation with fast and large response. By using this actuator as mechanical power and designing a robot configuration with self-feedback loop to generate self-oscillation, an inchworm-like actuator that can crawl autonomously towards the light source is constructed. Moreover, due to the anisotropy and tailorability of the actuator, an artificial crab robot that can simulate the sideways locomotion of crabs and simultaneously change color under light irradiation is also realized.

12.
Angew Chem Int Ed Engl ; 60(39): 21295-21303, 2021 Sep 20.
Artículo en Inglés | MEDLINE | ID: mdl-34184395

RESUMEN

Advanced two-dimensional nanosheets that promote the dynamic transportation and storage capacity of ions are significant for high-performance electrochemical capacitors (ECs). However, such materials often possess a low energy density. We have developed an ordered heteroarchitecture of molybdenum disulfide-carbon nanotubes (MoS2 -CNTs) in which CNTs are vertically grafted within a MoS2 framework by C-Mo covalent bonds. Benefiting from this in situ vertical bridge, high-speed interlaminar conductivity, unimpeded ion-diffusion channels and sufficient pseudocapacitive reactivity, the MoS2 -CNTs presents ultralarge capacitance (5485 F g-1 ) and good structural stability in potassium hydroxide electrolyte. Moreover, the all-unified solid-state flexible ECs obtained through direct-write printing construction deliver high energy density (226 mWh g-1 ), good capacitance (723 F g-1 ) and stable high/low-temperature operating ability, which can power a wearable health-monitoring device.

13.
Materials (Basel) ; 14(11)2021 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-34073207

RESUMEN

In this study, we have successfully prepared a free-standing Si/void/rGO yolk-shell structured electrode via the electrostatic self-assembly using protonated chitosan. When graphene oxide (GO) is dispersed in water, its carboxyl and hydroxyl groups on the surface are ionized, resulting in the high electronegativity of GO. Meanwhile, chitosan monomer contains -NH2 and -OH groups, forming highly electropositive protonated chitosan in acidic medium. During the electrostatic interaction between GO and chitosan, which results in a rapid coagulation phenomenon, Si/SiO2 nanoparticles dispersed in GO can be uniformly encapsulated between GO sheets. The free-standing Si/void/rGO film can be obtained by freeze-drying, high-pressure compression, thermal reduction and HF etching technology. Our investigation shows that after 200 charge/discharge cycles at the current density of 200 mA·g-1, the specific discharge capacity of the free-standing electrode remains at 1129.2 mAh·g-1. When the current density is increased to 4000 mA·g-1, the electrode still has a specific capacity of 469.2 mAh·g-1, showing good rate performance. This free-standing electrode with a yolk-shell structure shows potential applications in the field of flexible lithium-ion batteries.

14.
Polymers (Basel) ; 13(11)2021 May 22.
Artículo en Inglés | MEDLINE | ID: mdl-34067259

RESUMEN

The uniform dispersion of graphene oxide (GO) and strong interfacial bonding are the key factors in achieving the high mechanical strength of GO/polymer composites. It is still challenging to prepare GO/PA66 composites with uniform GO dispersion by the in situ polymerization method. In this paper, we prepare GO/PA66 salt nanocomposite by in situ precipitating PA66 salt with GO in ethanol. The GO/PA66 nanocomposite fibers are then fabricated using the as-prepared GO/PA66 salt by in situ polymerizing and melt spinning. By tuning the GO content, the tensile strength and Young's modulus of the GO/PA66 fibers are increased from 265 ± 18 to 710 ± 14 MPa (containing 0.3 wt% GO) and from 1.1 ± 0.08 to 3.8 ± 0.19 GPa (containing 0.5 wt% GO), respectively. The remarkable improvements are attributed to the uniform dispersion of GO in the GO/PA66 salt nanocomposite via ionic bonding and hydrogen bonding in the in situ precipitation process, and the covalent interfacial bonding between the GO and PA66 during the in situ polymerization process. This work sheds light on the easy fabrication of high-performance PA66-based nanocomposites.

15.
ACS Nano ; 15(6): 9273-9298, 2021 Jun 22.
Artículo en Inglés | MEDLINE | ID: mdl-34018737

RESUMEN

Soft electro-chemo-mechanical actuators have received enormous interest in biomimetic technologies, wearable electronics, and microelectromechanical systems due to their low voltage-driven large deformation, fast response, high strain, and working durability. Two-dimensional (2D) nanosheets, which can highly promote ion-induced micromotion to macrodeformation, have outstandingly been used as prime actuator electrodes because of their ordered microstructures, tunable interlayer spaces, controllable electrochemical activities, and excellent electrical and mechanical properties. Here, this review primarily focuses on the recent advances in key 2D electro-chemo-mechanical actuator electrodes, including graphene, MXenes, graphitic carbon nitride, molybdenum disulfide, black phosphorus, and graphdiyne. Various synthetic strategies of electrode design, such as microstructural architecture, active-site regulation, and channel construction, for achieving high ionic kinetic transport, charge storage, and electrochemical-mechanical performances are discussed. The advanced structures with diverse building principles that provide ordered and active ionic pathways for high actuation speed and strain are emphasized. Furthermore, the innovative applications of electro-chemo-mechanical actuators toward biomimetic robots and smart devices are highlighted. Finally, the current challenges and future perspectives are also proposed. The aim of this review is to provide the guiding significance for scientific researchers and industrial engineers to design higher performance next-generation electro-chemo-mechanical actuators.

16.
Adv Mater ; 33(22): e2100745, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33876867

RESUMEN

High-entropy materials are new-generation electrocatalysts for water splitting due to their excellent reactivity and highly tailorable electrochemical properties. Herein, a powerful top-level design strategy is reported to guide and design advanced high-entropy electrocatalysts by establishing reaction models (e.g., reaction energy barrier, conductivity, adsorption geometries for intermediates, and rate-determining step) to predict performance with the help of density functional theory (DFT) calculations. Accordingly, novel high-entropy Co-Cu-Fe-Mo (oxy)hydroxide electrocatalysts are fabricated by a new low-temperature electrochemical reconstruction method and their oxygen evolution reaction (OER) properties are thoroughly characterized. These as-prepared quaternary metallic (oxy)hydroxides present much better OER performance than ternary Co-Cu-Mo (oxy)hydroxide, Co-Fe-Mo (oxy)hydroxide, and other counterparts, and are demonstrated with a low overpotential of 199 mV at a current density of 10 mA cm-2 and a 48.8 mV dec-1 Tafel slope in 1 m KOH and excellent stability without decay over 72 h. The performance enhancement mechanism is also unraveled by synchrotron radiation. The work verifies the usefulness of high-entropy design and the great synergistic effect on OER performance by the incorporation of four elements, and also provides a new method for the construction of advanced high-entropy materials for energy conversion and storage.

17.
Angew Chem Int Ed Engl ; 60(18): 10366-10374, 2021 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-33594767

RESUMEN

We develop hetero-nanostructured black phosphorus/metal-organic framework hybrids formed by P-O-Co covalent bonding based on a designed droplet microfluidic strategy consisting of confined and ultrafast microdroplet reactions. The resulting hybrid exhibits large capacitance (1347 F g-1 ) in KOH electrolytes due to its large specific-surface-area (632.47 m2 g-1 ), well-developed micro-porosity (0.38 cm3 g-1 ), and engineered electroactivity. Furthermore, the proposed 3D printing method allows to construct all-integrated solid-state supercapacitor, which maintains interconnected porous network, good interfacial adhesion, and robust flexibility for short-path diffusion and excessive accommodation of ions. Consequently, the fabricated flexible supercapacitor delivers ultrahigh volumetric energy density of 109.8 mWh cm-3 , large capacitance of 506 F cm-3 , and good long-term stability of 12000 cycles.

18.
ACS Omega ; 5(7): 3397-3404, 2020 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-32118154

RESUMEN

To fully understand the chemical structure of graphene oxide and the oxidation chemistry of sp2 carbon sites, we conducted a practical experiment and density functional theory combined study on the oxidation process of graphite. The nuclear magnetic resonance, thermogravimetric analysis, and X-ray photoelectron spectroscopy results of unhydrolyzed oxidized graphite indicate that the oxidation process involves the intercalating oxidation, where electrically neutral species is the oxidizing agent, and the diffusive-oxidation, where MnO3 + is the oxidizing agent. An intrinsic formation and conversion path of oxygen-containing functional groups is proposed based on the experimental results and further interpreted with the aid of frontier molecular orbital theory and density functional theory. Meanwhile, the two unique features of the oxidation process of graphite, the chemistry stability of oxygen-containing functional groups in the strong oxidizing medium, and the self-regulation of the oxidation process are theoretically reasoned.

19.
Materials (Basel) ; 12(10)2019 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-31091720

RESUMEN

Titanates materials have attracted considerable interest due to their unusual functional and structural properties for many applications such as high-performance composites, devices, etc. Thus, the development of a large-scale synthesis method for preparing high-quality titanates at a low cost is desired. In this study, a series of quaternary titanates including K0.8Mg0.4Ti1.6O4, Na0.9Mg0.45Ti1.55O4, Na0.75Fe0.75Ti0.25O2, NaFeTiO4, and K2.3Fe2.3Ti5.7O16 are synthesized by a simple molten salt method using inexpensive salts of KCl and NaCl. The starting materials, intermediate products, final products, and their transformations were studied by using TG-DSC, XRD, SEM, and EDS. The results show that the grain size, morphology, and chemical composition of the synthesized quaternary titanates can be controlled simply by varying the experimental conditions. The molar ratio of mixed molten salts is critical to the morphology of products. When KCl:NaCl = 3:1, the morphology of K0.8Mg0.4Ti1.6O4 changes from platelet to board and then bar-like by increasing the molar ratio of molten salt (KCl-NaCl) to raw materials from 0.7 to 2.5. NaFeTiO4 needles and Na0.75Fe0.75Ti0.25O2 platelets are obtained when the molar ratio of molten salt (NaCl) to raw materials is 4. Pure phase of Na0.9Mg0.45Ti1.55O4 and K2.3Fe2.3Ti5.7O16 are also observed. The formation and growth mechanisms of both potassium magnesium titanates and sodium iron titanates are discussed based on the characterization results.

20.
RSC Adv ; 9(71): 41817-41823, 2019 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-35541617

RESUMEN

High-performance microwave absorbing materials require optimized impedance matching and high attenuation ability. Here we meet the challenge by incorporating electric loss with magnetic loss materials to prepare carbon-based/magnetic hybrids. The reduced graphene oxide (rGO)/La0.7Sr0.3MnO3 (LSMO) composites were prepared by dispersing the LSMO powders into 4.25, 6.25, 8.16, and 10 wt% of the graphene oxide aqueous solution, then the rGO/LSMO composites were formed by hydrothermal method. The pure rGO, LSMO, and rGO/LSMO composites were studied using X-ray diffraction and SEM. Microwave absorption properties were investigated by using coin method. Simulation studies show that 6.25 wt% of rGO/LSMO in a wax matrix exhibits the strongest reflection loss of -47.9 dB @ 10.7 GHz at a thickness of 2.5 mm. Moreover, the effective absorption bandwidth with the reflection loss below -10 dB is up to 14.5 GHz, ranged from 3.5 to 18 GHz for the composites with a thickness of 1.5-5.5 mm, due to a synergism between dielectric loss of rGO and magnetic loss of magnetic LSMO, which is an interesting exploration in the applications of rGO and LSMO. This method can be extended to design and fabricate hybrid absorbers with effective microwave absorption.

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