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1.
J Mater Sci Mater Med ; 35(1): 42, 2024 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-39073469

RESUMO

Studies have shown that the inhibition of phosphatase and tensin homolog deleted on chromosome 10 (PTEN)was neuroprotective against ischemia/reperfusion(I/R) injury. Bisperoxovanadium (bpV), a derivative of vanadate, is a well-established inhibitor of PTEN. However, its function islimited due to its general inadequacy in penetrating cell membranes. Mxene(Ti3C2Tx) is a novel two-dimensional lamellar nanomaterial with an excellent ability to penetrate the cell membrane. Yet, the effects of this nanomaterial on nervous system diseases have yet to be scrutinized. Here, Mxene(Ti3C2Tx) was used for the first time to carry bpV(HOpic), creating a new nanocomposite Mxene-bpV that was probed in a cerebral I/R injury model. The findings showed that this synthetic Mxene-bpV was adequately stable and can cross the cell membraneeasily. We observed that Mxene-bpV treatment significantly increased the survival rate of oxygen glucose deprivation/reperfusion(OGD/R)--insulted neurons, reduced infarct sizes and promoted the recovery of brain function after mice cerebral I/R injury. Crucially, Mxene-bpV treatment was more therapeutically efficient than bpV(HOpic) treatment alone over the same period. Mechanistically, Mxene-bpV inhibited the enzyme activity of PTEN in vitro and in vivo. It also promoted the expression of phospho-Akt (Ser473) by repressing PTEN and then activated the Akt pathway to boost cell survival. Additionally, in PTEN transgenic mice, Mxene-bpV suppressed I/R-induced inflammatory response by promoting M2 microglial polarization through PTEN inhibition. Collectively, the nanosynthetic Mxene-bpV inhibited PTEN' enzymatic activity by activating Akt pathway and promoting M2 microglial polarization, and finally exerted neuroprotection against cerebral I/R injury.


Assuntos
Microglia , Fármacos Neuroprotetores , PTEN Fosfo-Hidrolase , Proteínas Proto-Oncogênicas c-akt , Traumatismo por Reperfusão , Transdução de Sinais , Compostos de Vanádio , Animais , Microglia/efeitos dos fármacos , Microglia/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Camundongos , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/prevenção & controle , Transdução de Sinais/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Compostos de Vanádio/farmacologia , Compostos de Vanádio/química , PTEN Fosfo-Hidrolase/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/patologia , Polaridade Celular/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Nanocompostos/química
2.
Molecules ; 29(1)2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38202785

RESUMO

Real-time sensing of hydrogen sulfide (H2S) at room temperature is important to ensure the safety of humans and the environment. Four kinds of different nanocomposites, such as MXene Ti3C2Tx, Ti3AlC2, WS2, and MoSe2/NiCo2O4, were synthesized using the hydrothermal method in this paper. Initially, the intrinsic properties of the synthesized nanocomposites were studied using different techniques. P-type butane and H2S-sensing behaviors of nanocomposites were performed and analyzed deeply. Four sensor sheets were fabricated using a spin-coating method. The gas sensor was distinctly part of the chemiresistor class. The MXene Ti3C2Tx/NiCo2O4-based gas sensor detected the highest response (16) toward 10 ppm H2S at room temperature. In comparison, the sensor detected the highest response (9.8) toward 4000 ppm butane at 90 °C compared with the other three fabricated sensors (Ti3AlC2, WS2, and MoSe2/NiCo2O4). The MXene Ti3C2Tx/NiCo2O4 sensor showed excellent responses, minimum limits of detection (0.1 ppm H2S and 5 ppm butane), long-term stability, and good reproducibility compared with the other fabricated sensors. The highest sensing properties toward H2S and butane were accredited to p-p heterojunctions, higher BET surface areas, increased oxygen species, etc. These simply synthesized nanocomposites and fabricated sensors present a novel method for tracing H2S and butane at the lowest concentration to prevent different gas-exposure-related diseases.

3.
Mikrochim Acta ; 189(2): 59, 2022 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-35015150

RESUMO

A  nanocomposite of rGO/MXene-Pd/rGO with hierarchical structure based on Ti3C2Tx MXene, Pd nanoparticles, and reduced graphene oxide (rGO) was synthesized by a green approach. Ti3C2Tx MXene decorated with Pd nanoparticles (MXene-Pd) was prepared first. Then, graphene oxide (GO), MXene-Pd, and GO were coated on the surface of the glassy carbon electrode (GCE) in sequence. After each coating of the GO layer, the GO nanosheets were reduced to rGO electrochemically. The fabricated rGO/MXene-Pd/rGO hierarchical framework performs a pie structure with MXene-Pd as the stuffing and rGO nanosheets as the crust, which will be beneficial to the enhancement of its electrochemical sensing performance. As compared with other electrodes, the rGO/MXene-Pd/rGO/GCE exhibited higher electrocatalytic activity and better sensing performance for luteolin detection, with a wide linear range of 6.0 × 10-10 to 8 × 10-7 M and 1.0 × 10-6 to 1.0 × 10-5 M (oxidation peak potential Epa = 0.34 V vs. SCE), a low detection limit of 2.0 × 10-10 M, and a high sensitivity of 112.72 µA µM-1 cm-2. Moreover, the fabricated sensor also showed high selectivity, reproducibility, and repeatability toward the detection of luteolin. The real sample analysis for luteolin in honeysuckle was successfully carried out by rGO/MXene-Pd/rGO and verified with high-performance liquid chromatography (HPLC) analysis techniques with acceptable results. All the above tests indicate the promising application prospect of the rGO/MXene-Pd/rGO framework for luteolin detection in honeysuckle and other herbs containing luteolin.


Assuntos
Técnicas Eletroquímicas , Grafite , Luteolina , Paládio , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Grafite/química , Luteolina/química , Paládio/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
4.
Small ; 15(25): e1900107, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31066210

RESUMO

Two-dimensional (2D) materials have attracted extensive research interest in academia due to their excellent electrochemical properties and broad application prospects. Among them, 2D transition metal carbides (Ti3 C2 Tx ) show semiconductor characteristics and are studied widely. However, there are few academic reports on the use of 2D MXene materials as memristors. In this work, reported is a memristor based on MXene Ti3 C2 Tx flakes. After electroforming, Al/Ti3 C2 Tx /Pt devices exhibit repeatable resistive switching (RS) behavior. More interestingly, the resistance of this device can be continuously modulated under the pulse sequence with 10 ns pulse width, and the pulse width of 10 ns is much lower than that in other reported work. Moreover, on the nanosecond scale, the transition from short-term plasticity to long-term plasticity is achieved. These two properties indicate that this device is favorable for ultrafast biological synapse applications and high-efficiency training of neural networks. Through the exploration of the microstructure, Ti vacancies and partial oxidation are proposed as the origins of the physical mechanism of RS behavior. This work reveals that 2D MXene Ti3 C2 Tx flakes have excellent potential for use in memristor devices, which may open the door for more functions and applications.

5.
Angew Chem Int Ed Engl ; 58(51): 18524-18529, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31617307

RESUMO

Lamellar membranes with well-defined 2D nanochannels show fast, selective permeation, but the underlying molecular transport mechanism is unexplored. Now, regular robust MXene Ti3 C2 Tx lamellar membranes are prepared, and the size and wettability of nanochannels are manipulated by chemically grafted hydrophilic (-NH2 ) or hydrophobic (-C6 H5 , -C12 H25 ) groups. These nanochannels have a sharp difference in mass transfer behavior. Hydrophilic nanochannels, in which polar molecules form orderly aligned aggregates along channel walls, impart ultrahigh permeance (>3000 L m-2 h-1 bar-1 ), which is more than three times higher than that in hydrophobic nanochannels with disordered molecular configuration. In contrast, nonpolar molecules with disordered configuration in both hydrophilic and hydrophobic nanochannels have comparable permeance. Two phenomenological transport models correlate the permeance with the mass transport mechanism of molecules that display ordered and disordered configuration.

6.
Small ; 14(41): e1802443, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30175545

RESUMO

Being conductive and flexible, 2D transition metal nitrides and carbides (MXenes) can serve in Li-S batteries as sulfur hosts to increase the conductivity and alleviate the volume expansion. However, the surface functional groups, such as OH and F, weaken the ability of bare MXenes in the chemisorption of polysulfides. Besides, they create numerous hydrogen bonds which make MXenes liable to restack, resulting in substantial loss of active area and, thus, inaccessibility of ions and electrolyte. Herein, a facile, one-step strategy is developed for the growth of TiO2 quantum dots (QDs) on ultrathin MXene (Ti3 C2 Tx ) nanosheets by cetyltrimethylammonium bromide-assisted solvothermal synthesis. These QDs act as spacers to isolate the MXene nanosheets from restacking, and preserve their 2D geometry which guarantees larger electrode-electrolyte contact area and higher sulfur loading. The stronger adsorption energy of polysulfides with TiO2 (than with Ti3 C2 Tx ), as proven by density functional theory calculations, is essential for better on-site polysulfide retention. The ultrathin nature and protected conductivity ensure rapid ion and electron diffusion, and the excellent flexibility maintains high mechanical integrity. In result, the TiO2 QDs@MXene/S cathode exhibits significantly improved long-term cyclability and rate capability, disclosing a new opportunity toward fast and stable Li-S batteries.

7.
Int J Biol Macromol ; 265(Pt 2): 130520, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38553390

RESUMO

Starch-derived films exhibit significant potential for packaging applications owing to their low cost, biodegradable characteristics, and natural abundance. Nonetheless, there is a demand to enhance their mechanical properties and moisture resistance to broaden their use. In this study, high performing sorbitol-plasticized starch/Ti3C2Tx MXene nanocomposites, reinforced with ultra-low filler contents, were fabricated for the first time in literature. The MXene nanoplatelets were well-dispersed within the starch matrix while there was a tendency for the fillers to align in-plane, as revealed by polarized Raman spectroscopy. The produced nanocomposite films demonstrate remarkable effectiveness in blocking UV light, offering an additional valuable attribute in food packaging. The Young's modulus and tensile strength of starch films containing 0.75 wt% MXene increased from 439.9 and 11.0 MPa to 764.3 and 20.8 MPa, respectively. The introduction of 1 wt% MXene nanoplatelets reduced the water vapour permeability of starch films from 2.78 × 10-7 to 1.80 × 10-7 g/m h Pa due to the creation of highly tortuous paths for water molecules. Micromechanical theories were also implemented to understand further the reinforcing mechanisms in the biobased nanocomposites. The produced starch nanocomposites not only capitalize on the biodegradable and renewable nature of starch but also harness the unique properties of nanomaterials, paving the way for sustainable and high-performance packaging solutions that align with both consumer and environmental demands.


Assuntos
Nanocompostos , Nitritos , Amido , Elementos de Transição , Amido/química , Titânio/química , Nanocompostos/química , Resistência à Tração , Embalagem de Alimentos/métodos
8.
ACS Appl Mater Interfaces ; 16(12): 15514-15524, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38488069

RESUMO

With the increasing development of nanomaterials, the construction of multiscale nanostructured interphase has emerged as a viable technique to reinforce carbon fiber-reinforced polymer composites. Here, "flexible" aramid nanofibers (ANFs) were first introduced on the surface of carbon fibers (CF) by electrophoretic deposition (EPD), and then "rigid" MXene sheets were grafted by ultrasonic impregnation. This feasible two-step treatment introduces a hierarchical "rigid-flexible" structure at the CF/polyamide (PA) interface. Results showed that this "rigid-flexible" multilayer structure improved the roughness, chemical bonding, mechanical interlocking, and wettability of CF/PA composites. At the same time, the modulus variation between the fiber and the matrix is significantly smoothed due to the increased thickness of the interfacial layer, increasing the payload transfer from the PA matrix to the fiber and decreasing the stress concentration. Compared to the desized CF, the interlaminar shear strength (ILSS) and tensile strength of the modified CF-ANF@MX0.2/PA composite increased by 50.02 and 36.11%, respectively. This innovative interfacial design and feasible treatment method facilitate the construction of firmly interacting interfacial layers in CF/PA composites, offering broad prospects for the production of high-performance CF/PA composites.

9.
J Colloid Interface Sci ; 650(Pt B): 995-1002, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37459731

RESUMO

The developments in hydrogen evolution reaction (HER) and supercapacitor technologies for electrochemical energy storage and conversion have received considerable attention. Although MoS2 is electrochemically active for both HER and supercapacitors, limited active sites, slow ionic transport, and poor conductivity lead to its poor capacitance and electrocatalytic activity. Herein, hierarchical Ti3C2Tx/MoS2/Ti3C2Tx@CC (TMT@CC) composites were well-designed as electrodes for both HER and supercapacitors. Flexible TMT@CC electrodes with an area as large as âˆ¼ 80 cm2 and optimal mass-loading of 17.9 mg cm-2 were achieved. The inner layer Ti3C2Tx in the composites provides ideal nucleation sites for the growth of MoS2 arrays, and the outermost Ti3C2Tx effectively anchors the vertically arrayed MoS2. The hierarchically vertical structure provides strong interfacial coupling and shortens ion diffusion paths, leading to high stability and fast ion/electron transport kinetics. Due to such a synergistic effect, the flexible binder-free TMT@CC electrodes exhibited high areal capacitance (5.06 F cm-2 at 5 mA cm-2) for supercapacitors and low overpotential (119 mV versus RHE at 10 mA cm-2) for HER catalyst. Furthermore, a high energy density of 0.125 mWh cm-2 at a power density of 1.5 mW cm-2 has been achieved from the TMT@CC-based symmetric supercapacitor. Our strategy can be expanded to other vertically arrayed hierarchical structures as electrode materials of efficient HER and supercapacitors.

10.
Int J Biol Macromol ; 243: 125195, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-37270119

RESUMO

Electromagnetic (EM) pollution has become a serious problem in modern society as it affects human lives. The fabrication of strong and highly flexible materials for electromagnetic interference (EMI) shielding applications is extremely urgent. Herein, a MXene Ti3C2Tx/Fe3O4 & bacterial cellulose (BC)/Fe3O4&Methyltrimethoxysilane (MTMS) flexible hydrophobic electromagnetic shielding film (SBTFX-Y, X and Y were the number of layers of BC/Fe3O4 and the layers of Ti3C2Tx/Fe3O4), was fabricated. In the prepared film, MXene Ti3C2Tx absorbs a large amount of radio waves through polarization relaxation and conduction loss. Because of its extremely low reflectance of electromagnetic waves, BC@Fe3O4, as the outermost layer of the material, allows more electromagnetic waves to incident inside the material. The maximum electromagnetic interference (EMI) shielding efficiency (SE) of 68 dB was achieved for the composite film at 45 µm thickness. What's more, the SBTFX-Y films show excellent mechanical properties, hydrophobicity and flexibility. The unique stratified structure of the film provides a new strategy for designing high-performance EMI shielding films with excellent surface and mechanical properties.


Assuntos
Bactérias , Fenômenos Eletromagnéticos , Humanos , Celulose , Poluição Ambiental
11.
Membranes (Basel) ; 13(4)2023 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-37103857

RESUMO

Polyvinyl alcohol (PVA) pervaporation (PV) membranes have been extensively studied in the field of ethanol dehydration. The incorporation of two-dimensional (2D) nanomaterials into the PVA matrix can greatly improve the hydrophilicity of the PVA polymer matrix, thereby enhancing its PV performance. In this work, self-made MXene (Ti3C2Tx-based) nanosheets were dispersed in the PVA polymer matrix, and the composite membranes were fabricated by homemade ultrasonic spraying equipment with poly(tetrafluoroethylene) (PTFE) electrospun nanofibrous membrane as support. Due to the gentle coating of ultrasonic spraying and following continuous steps of drying and thermal crosslinking, a thin (~1.5 µm), homogenous and defect-free PVA-based separation layer was fabricated on the PTFE support. The prepared rolls of the PVA composite membranes were investigated systematically. The PV performance of the membrane was significantly improved by increasing the solubility and diffusion rate of the membranes to the water molecules through the hydrophilic channels constructed by the MXene nanosheets in the membrane matrix. The water flux and separation factor of the PVA/MXene mixed matrix membrane (MMM) were dramatically increased to 1.21 kg·m-2·h-1 and 1126.8, respectively. With high mechanical strength and structural stability, the prepared PGM-0 membrane suffered 300 h of the PV test without any performance degradation. Considering the promising results, it is likely that the membrane would improve the efficiency of the PV process and reduce energy consumption in the ethanol dehydration.

12.
Front Bioeng Biotechnol ; 10: 1028470, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36277391

RESUMO

Uveal melanoma (UM) is a highly malignant intraocular tumor with poor prognosis. Current topical ophthalmic therapies purpose to conserve the eye and useful vision. Due to the risks and limited clinical benefits, the topical treatments of UM remain challenging and complex. In this study, newly developed non-oxidized MXene-Ti3C2Tx quantum dots (NMQDs-Ti3C2Tx) are proposed for UM treatment. Surprisingly, NMQDs-Ti3C2Tx shows significant tumor-killing effects on UM cells in a dose-dependent manner and causes severe necrosis near the injection site on the xenograft UM tumor model. Moreover, NMQDs-Ti3C2Tx exhibits excellent biocompatibility with normal retina pigment epithelium (RPE) cells and does not cause any damage in C57BL/6 mice eyes. Mechanistically, NMQDs-Ti3C2Tx inhibits the proliferation, invasion, and migration of UM cells via its desirable reactive oxygen species (ROS) generation ability, which causes lipid peroxidation and mitophagy, triggering cell ferroptosis. Furthermore, NMQDs-Ti3C2Tx is detected accumulating in autolysosomes which exacerbates cell death. This work provides new light on the topical treatment of UM.

13.
Nanomaterials (Basel) ; 12(16)2022 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-36014616

RESUMO

A high absorption broadband absorber based on MXene and tungsten nanospheres in visible and near-infrared bands is proposed. The absorber has a maximum absorption of 100% and an average absorption of 95% in the wavelength range of 400-2500 nm. The theoretical mechanism and parameter adjustability of the absorber are analyzed by FDTD solutions. The results show that the structural parameters can effectively adjust the absorption performance. The good absorption performance is due to the action of the local surface plasmon resonance coupling with the gap surface plasmon resonance and Fabry-Perot resonance. The simulation results show that the absorber is insensitive to the polarization and oblique incidence angle of incident light, and that high absorption and broadband can be maintained when the oblique incidence angle is up to 60°.

14.
Polymers (Basel) ; 13(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072885

RESUMO

As a member of two-dimensional (2D) materials, MXene is an ideal reinforcement phase for modified polymers due to its large number of polar functional groups on the surface. However, it is still relatively difficult to modify any functional groups on the surface of MXene at present, which limits its application in enhancing some polymers. Herein, one-dimensional (1D) attapulgite (ATP) nanomaterials were introduced onto the surface of MXene to form ATP-MXene hybrids, which successfully improved the mechanical properties of the epoxy composites. ATP with appropriate content can increase the surface roughness of the MXene lamellae to obtain better interface interaction. Therefore, remarkable enhancement on the mechanical property was achieved by adding M02A025 (0.2 wt % MXene and 0.25 wt % ATP), which is the optimum composition in the hybrids for composite mechanical properties. Compared to neat epoxy, the tensile strength, flexural strength and critical stress intensity factor (KIC) of M02A025/epoxy are increased by 88%, 57%, and 195%, respectively, showing a high application prospect.

15.
Polymers (Basel) ; 13(11)2021 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-34072938

RESUMO

The surface modification technology of carbon fibers (CFs) have achieved considerable development, and it has achieved great success in improving the interfacial shear strength (IFSS) of the polymer matrix. Among them, MXene (Ti3C2Tx) functionalized CFs have been proven to improve the interface performance significantly. Unfortunately, the results on the microscopic scale are rarely applied to the preparation of macroscopic composite materials. Herein, the process of MXene functionalized CFs were attempted to be extended to short carbon fibers (SCFs) and used to strengthen epoxy materials. The results show that the cross-scale reinforcement of MXene functionalized SCFs can be firmly bonded to the epoxy matrix, which significantly improves the mechanical properties. Compared to neat epoxy, the tensile strength (141.2 ± 2.3 MPa), flexural strength (199.3 ± 8.9 MPa) and critical stress intensity factor (KIC, 2.34 ± 0.04 MPa·m1/2) are increased by 100%, 67%, and 216%, respectively.

16.
ACS Appl Mater Interfaces ; 12(37): 42294-42301, 2020 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-32833428

RESUMO

The formation of uniform sheets of exfoliated MXene over a large area is important for improving their performance in practical applications. In this study, the Langmuir-Schaefer technique was employed to deposit uniform MXene sheets on a solid substrate and control the morphological structure over a large area. At the liquid-gas interface, MXene flakes were densely compressed into nanosheets with minimal gaps between them at 20 mN/m. Through further compression, the wrinkle morphologies of MXene sheets tend to be perpendicularly aligned to the compression direction. These wrinkle structures were also exhibited when MXene sheets were mixed in equal proportions with graphene oxide sheets. Owing to the close correlation of the morphologies of MXene films with the performance of MXene-based materials, the technique employed in this study can provide a route for applications requiring wrinkled MXene, ranging from nanoelectronic devices to energy storage materials, such as supercapacitors and battery electrodes.

17.
Chem Asian J ; 15(7): 1044-1051, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32052584

RESUMO

In this work, we studied the formation of the rutile phase of titanium dioxide (TiO2 ) on delaminated MXene (d-Ti3 C2 Tx ) flakes by the reaction of Ti3 C2 Tx with amino acids in water. Three types of amino acids with varied side-chain polarity were used to delaminate Ti3 C2 Tx . d-Ti3 C2 Tx flakes formed stable colloidal solutions due to the negative surface charges of chemisorbed amino acids on the d-Ti3 C2 Tx . Rutile formed on d-Ti3 C2 Tx at room temperature upon the intercalation of aromatic amino acids and subsequent sonication of the solution, while flakes intercalated with aliphatic amino acids did not oxidize. X-Ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy revealed the nanosize rutile formation on the surface of Ti3 C2 Tx flakes. The XPS results indicated the surface functionalization of histidine on d-Ti3 C2 Tx flakes. As-synthesized histidine functionalized rutile TiO2 @d-Ti3 C2 Tx hybrid was used for adsorption of Cu2+ ions from aqueous solution with a maximum uptake of 95 mg g-1 .

18.
Nanomaterials (Basel) ; 10(9)2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32858800

RESUMO

As a typical two-dimensional material, MXene possesses excellent conductivity and tunable interlayer space, which makes it have an impressive development potential in the field of electromagnetic (EM) waves absorbing materials. In this work, we fabricated a sandwich structure CoS@Ti3C2Tx composite using a simple solvothermal process. The CoS nanoparticles are anchored on the Ti3C2Tx MXene sheets, forming a heterolayered structure. The results demonstrate that the CoS@Ti3C2Tx composites with the sandwich-like architecture showed excellent EM absorbing performance due to the synergistic effects of the conductivity loss, interface polarization, and dipole polarization. When the doping ratio was 40 wt %, the maximum reflection loss value of CoS@Ti3C2Tx was up to -59.2 dB at 14.6 GHz, and the corresponding effective absorption bandwidth (below -10 dB) reached 5.0 GHz when the thickness was only 2.0 mm. This work endows a new candidate for the design of MXene-based absorption materials with optimal performance.

19.
ACS Appl Mater Interfaces ; 12(12): 13750-13758, 2020 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-32125143

RESUMO

Capacitive deionization (CDI) has become a promising method to solve the shortage of freshwater resources recently. However, the co-ion expulsion effect obviously hinders electrosorption capacity and charge efficiency of CDI. In this work, an asymmetric CDI cell is assembled in which Na+-intercalated Ti3C2Tx (NaOH-Ti3C2Tx) serves as a cation-selective cathode, while the activated carbon (AC) serves as the anode. The NaOH-Ti3C2Tx with negatively charged surface groups (-OH, -O, and -F) is adopted to weaken the co-ion expulsion effect. Benefited from the synergistic effect of the reduced co-ion expulsion effect and expanded interlayer space, the asymmetric CDI cell achieves a higher electrosorption capacity of 12.19 mg g-1 and a higher charge efficiency of 0.826 compared with the symmetric one composed of AC (4.55 mg g-1 and 0.306) in 100 mg L-1 NaCl solution. High cyclic stability of the as-prepared asymmetric CDI cell is also observed. The improved desalination performance indicates that NaOH-Ti3C2Tx is a promising alternative as cation-selective cathode material for asymmetric CDI cells. The desalination mechanism is discussed in detail to lay the foundation for further improvement of the CDI performance of other 2D materials like MXene.

20.
ACS Nano ; 14(7): 8744-8753, 2020 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-32628449

RESUMO

Sodium (Na) metal batteries have attracted increasing attention and gained rapid development. However, the processing, storing, and application of Na metal anodes are restricted by its inherent stickiness and poor mechanical properties. Herein, an MXene (Ti3C2Tx)-coated carbon cloth (Ti3C2Tx-CC) host is designed and synthesized, which shows a highly metallic conductive and sodiophilic surface. After a thermal infusion treatment, a Na-Ti3C2Tx-CC composite with rigidity and bendability is obtained and employed as a metal anode for Na ion batteries. The Na-Ti3C2Tx-CC electrodes present stable cycling performance and high stripping/plating capacity in both an ether-based (up to 5 mA·h·cm-2) and a carbonate-based (up to 8 mA·h·cm-2) electrolyte. The fundamental protection mechanism of MXene Ti3C2Tx is investigated. Ti3C2Tx efficiently induces Na's initial nucleation and laterally oriented deposition, which effectively avoids the generation of mossy/dendritic Na. The arrangement of Na atoms deposited on the MXene surface inherits the MXene atomic architecture, leading to a smooth "sheet-like" Na surface. Meanwhile, a flexible Na-based Na-Ti3C2Tx-CC∥Na3V2(PO4)3 device is assembled and exhibits capable electrochemical performance.

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