首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
The proliferation of electronic devices and wireless communication is leading to serious electromagnetic (EM) interference. In this work, Ti3C2/cement composites were developed as high efficiency EM functional materials by introducing exfoliated Ti3C2Tx MXene with cement for green buildings with EM shielding function. In the composites, few-layered Ti3C2 MXene were dispersed homogeneously throughout the cement matrix. The EM properties of the composites were studied as a function of the MXene content. With increasing MXene content, real and imaginary part of permittivity was significantly improved owing to the polarization and electrical conduction caused by the MXene phase. Composites with 15 wt.% MXene showed good EM absorbing properties with a maximum effective absorbing bandwidth of 2.67 GHz. Strong EM shielding can be achieved when MXene content increased to 25 wt.%. The EM shielding effectiveness of such composites was higher than 22.0 dB, and the dominating shielding mechanism was EM absorption. This work finds new materials for the development of advanced green buildings with EM shielding function.  相似文献   

2.
《Ceramics International》2022,48(16):22845-22853
Effective electromagnetic interference (EMI) shielding materials have garnered substantial interest for their efficacy in attenuating electromagnetic wave energy, ensuring data confidentiality, ensuring the operational stability of fragile electronic systems. To begin, artificially cultured diatom frustules (DF)-derived porous silica (DFPS) skeletons were constructed as templates in this study. Porous ceramics hot-pressed at 800 °C displayed a high compressive strength with a high specific surface area due to their three-dimensional (3D) multilayered and porous structures. Then, mechanically robust Ti3C2Tx/DFPS composites with exceptional EMI shielding performance were fabricated by immersing porous DF-based ceramics into Ti3C2Tx solutions and annealing in an argon environment to increase the materials’ shielding efficiency (SE). The EMI SE of composites hot-pressed at 800 °C achieved the maximum EMI SE of 43.2 dB in the X-band and a compressive strength of 67.5 MPa, establishing a hitherto unreported balance of mechanical characteristics and shielding performance. Prolonged transmission paths, multiple dissipation, scattering and reflection of electromagnetic energy were achieved using a well-maintained hierarchical porous silica framework decorated with MXene, with adsorption caused by surface MXene serving as the primary shielding mechanism for the composites. Due to their superior overall performance, MXene/DFPS EMI shielding composites have a bright future in the aircraft sector as delicate electronic device components.  相似文献   

3.
《Ceramics International》2019,45(16):19902-19909
Two-dimensional (2D) MXenes have attracted much attention due to their unique structural characteristics and novel performance in a variety of functions. The fabrication of 2D Ti3C2 MXene by acid etching usually requires a long period of over 10 h. In this work, we report on the rapid preparation, thermal stability and electromagnetic interference (EMI) shielding effectiveness of 2D Ti3C2 MXene. With the processing conditions optimized by adjusting the etching time and temperature, Ti3C2 MXene with a scattered accordion-like structure has been successfully achieved by etching Ti3AlC2 powders with 40% HF at 50 °C for only 0.5 h. The as-synthesized Ti3C2 was stable at temperatures up to 300 °C in air, but stable in vacuum at temperatures up to 800 °C. The as-synthesized Ti3C2 MXene has good EMI shielding performance. The total shielding effectiveness of Ti3C2 in a WAX matrix exceeded 20 dB in the whole frequency ranging from 2 to 18 GHz. The maximum shielding effectiveness value achieved to 34 dB at 18 GHz as the Ti3C2 content was up to 70 wt%. This work provides an approach for the large scale preparation of the Ti3C2 MXene.  相似文献   

4.
《Ceramics International》2021,47(21):29995-30004
Novel and highly effective electromagnetic interference (EMI) shielding materials are desirable to attenuate unwanted electromagnetic radiation or interference produced by electrical communication devices. Here, functional Ti3C2Tx@Ni particles with a core@shell and sandwich like structure were fabricated using the facile electroless plating technique. The core@shell structured Ti3C2Tx@Ni consists of a Ti3C2Tx core and a Ni shell. In the core, thin Ni layers are sandwiched in between Ti3C2Tx flakes. EMI shielding effectiveness (SE) values of Ti3C2Tx@Ni/wax composites increased with increasing Ti3C2Tx@Ni content. The average EMI SE value of 60 wt% Ti3C2Tx@Ni/wax composite was 43.12 dB, increased by 73% as compared with 24.93 dB for the same content of pristine Ti3C2Tx in wax in the frequency range 2–18 GHz. An average EMI SE of 74.14 dB was achieved in the 80 wt% Ti3C2Tx@Ni/wax. The enhanced EMI shielding performance should be ascribed to the synergic effect of the absorption loss of the Ti3C2Tx core and the magnetic loss of the Ni shell and the inner Ni layers.  相似文献   

5.
《Ceramics International》2021,47(18):25531-25540
Ti3C2Tx exhibits excellent electromagnetic (EM) shielding and electrochemical properties. However, the inherent re-stacking tendency and easy oxidation of Ti3C2Tx limit its further application. In this study, a multi-walled carbon nanotube/polyaniline composite (CNT/PANI, denoted as C–P) was introduced into Ti3C2Tx nanosheets to obtain a Ti3C2Tx–CNT/PANI composite (T@CP). Owing to the integrated effects of Ti3C2Tx and C–P, the contribution of absorption was significantly improved, which finally enhanced the EM shielding performance of T@CP. The highest total EM shielding effectiveness (SET) was close to 50 dB (49.8 dB), which was substantially higher than that of pure Ti3C2Tx (45.3 dB). Moreover, T@CP demonstrated outstanding supercapacitive performance. The specific capacitance of T@CP (2134.5 mF/cm2 at 2 mV/s) was considerably higher than that of pure Ti3C2Tx (414.3 mF/cm2 at 2 mV/s). These findings provide a new route for the development of high-efficiency Ti3C2Tx-based bifunctional EM shielding and electrochemical materials.  相似文献   

6.
In this work, a robust and flexible bilayered MXene/cellulose paper sheet with superhigh electrical conductivity was prepared via vacuum-assisted filtration and a subsequent hot-pressing process for electromagnetic interference (EMI) shielding applications. By tightly assembling few-layered MXene (f-Ti3C2Tx) on the cellulose substrate via hydrogen bonds, an effective and interconnected conductive network was constructed in the paper sheet, resulting in a high electrical conductivity of 774.6–5935.4 S m?1 at various f-Ti3C2Tx loadings. The highly conductive MXene layer can promptly reflect a great amount of incident EM waves, a process which preceded the transmission of EM waves in the cellulose matrix. Owing to the highly efficient reflection-dominated EMI shielding mechanism, the resultant bilayered MXene/cellulose paper sheets exhibit excellent EMI shielding effectiveness of 34.9–60.1 dB and specific EMI shielding efficiency of 290.6–600.7 dB mm?1. Moreover, the MXene/cellulose paper sheets demonstrated improved mechanical strength (up to 25.7 MPa) and flexibility due to the mechanical frame effect acted by the cellulose substrate. Consequently, the robust and flexible bilayered MXene/cellulose paper sheet is a promising candidate for application in next-generation electric devices.  相似文献   

7.
Three-dimensional flower-like Ni(NiO) decorated on two-dimensional Ti3C2Tx/TiO2 composites were successfully synthesized by an in situ solvothermal reaction, and the electromagnetic (EM) wave absorption performance of the hybrids were explored at 2.00–18.00 GHz. The as-prepared Ni(NiO)/Ti3C2Tx/TiO2 composites include flower-like Ni(NiO) with uniform distribution on the surface of Ti3C2Tx MXenes and part of them get into the space between interlayers. The Ni(NiO)/Ti3C2Tx/TiO2 composites exhibit a maximum reflection loss (RL) value of ?41.74 dB at 14.96 GHz with the absorber thickness of merely 1.3 mm and the effective absorption bandwidth (EAB) reaches 3.20 GHz. The outstanding electromagnetic wave absorbing performance can be attributed to the dielectric loss of Ti3C2Tx MXenes and multi-phase heterostructures, the magnetic loss of Ni(NiO) and their synergistic loss mechanism. Moreover, the zigzag path formed by flower-like Ni(NiO) also has a great consumption effect on electromagnetic waves by incurring the eddy current under the affect of alternating EM waves. The laminated structure of Ti3C2Tx MXenes also dissipates microwaves by offering the space for multiple reflections and scattering. This paper furnished a novel modus for synthesizing original EM wave absorption materials and making the balance among thickness, broad bandwidth, oxidation resistance and light weight, which makes Ni(NiO)/Ti3C2Tx/TiO2 composites a hopeful material for microwave absorption (MA).  相似文献   

8.
《Ceramics International》2017,43(14):10757-10762
The recently developed two-dimensional transition metal carbides (such as MXene) have shown amazing electrical properties. MXene and derivative two dimensional (2D) materials are widely used in electron devices, and have large potential application in electromagnetic (EM) absorber. Herein we describe a mild method to prepare an urchin-like ZnO-MXene Ti3C2Tx nanocomposite through a coprecipitation process. The nanocomposite delivers a substantially enhanced EM absorbing performance with an optimum reflection loss of −26.30 dB, which is significantly better than that of primitive Ti3C2Tx (−6.70 dB), owing to the construction of unique semiconductive networks and larger interfaces. The EM absorption performance can be effectively controlled in the range of 14.0–18.0 bands by changing the growth time of ZnO. Considering the large amount of members in MXene, this study demonstrates a new strategy applicable in maximizing their applications in EM absorbing materials.  相似文献   

9.
Demand for high-performance electromagnetic (EM) wave absorbing materials with high-temperature resistance is always urgent for application in a harsh environment. In this contribution, two-dimensional material, Ti3C2Tx MXene, was introduced into a hyperbranched polyborosilazane. After pyrolyzation, the as-prepared TiC/SiBCN ceramics present excellent EM wave absorption in X-band. The TiC nanograins appearing after annealing provide multilevel reflection and interface polarization. Dipole polarization formed at interface defects, in company with interfacial polarization, also makes a great contribution to enhanced EM wave absorption. The TiC/SiBCN nanocomplex prepared with 5 wt% Ti3C2Tx MXene possesses a minimum reflection coefficient of −45.44 dB at 10.93 GHz and abroad bandwidth 8.4 and 12.4 GHz, almost covering the entire X-band. Tuning the thickness in the range of 2.35-2.54 mm, the effective absorption band can achieve the entire X-band. And the EM wave absorbing performance has been maintained to a large extent at 600°C with the minimum reflection coefficient of −26.12 dB at 12.13 GHz and the effective absorption bandwidth of 2 GHz. Last but not the least, TiC/SiBCN ceramics offer a good thermal stability in argon as well as in air atmosphere, making it possible to serve in high-temperature detrimental environments. This study is expected to provide a new perspective for the design of high-performance absorbing materials that are able to be used in harsh environments, especially in high temperatures.  相似文献   

10.
《Ceramics International》2022,48(17):24656-24665
This study aims to provide insights into the absorption and shielding performances of Fe3O4 modified oligo-layered Ti3C2Tx towards microwave electromagnetic interference. Oligo-layered Ti3C2Tx was modified by Fe3O4 nanoparticles (60 nm) via a facile electrostatic assembly approach at different loading rates. This composite was shown to have high dielectric constant and high permeability compared with oligo-layered Ti3C2Tx. The microwave electromagnetic absorbing and shielding performances were monitored through a vector network instrument with focuses on the EMI performance. The sample Ti3C2Tx/Fe3O4 with a 5:1 mass ratio of Ti3C2Tx to Fe3O4 displayed the optimized EMI shielding performance. The average SE value was 62.19 dB, and the maximum value was 68.72 dB at 18 GHz with a 2.6 mm thickness. The EMI shielding mechanism was understood based on the conductive loss, magnetic loss, dipole polarization, and multiple scattering. Results suggests that Ti3C2Tx/Fe3O4 composites are expected to be superior EMI shielding material.  相似文献   

11.
Ti3C2Tx MXene, an emerging two-dimensional (2D) ceramic material, has rich interfaces and strong conductive networks. Herein, we have successfully built a heterostructure between Ti3C2Tx MXene and WS2 to improve electromagnetic absorption performance. X-ray diffraction and X-ray photoelectron spectroscopy were used to determine the successful synthesis of Ti3C2Tx/WS2 composite. Field emission scanning electron microscopy and transmission electron microscopy images show that WS2 nanosheets are evenly dispersed on the accordion-like Ti3C2Tx MXene. Importantly, Ti3C2Tx MXene/WS2 composite has sufficiently high dielectric loss and impedance matching due to self-adjusting conductivity and 2D heterostructure interfaces. As a result, the Ti3C2Tx/WS2 composite has a minimum reflection loss (RLmin) of −61.06 dB at 13.28 GHz. Besides, it has a broad effective absorption bandwidth (EAB) of 6.5 GHz, with EAB >5.0 GHz covering a wide range of thickness. Such impressive results may provide experience for the application of Ti3C2Tx ceramics and 2D materials.  相似文献   

12.
MAX phases have emerged as promising corrosion-resistant electromagnetic interference (EMI) shielding materials. Herein, four MAX phases: Ti3SiC2, Ti3AlC2, V0.5Cr1.5AlC, and Nb4AlC3, were synthesized via solid–liquid reactions. The electrical conductivities of Ti3SiC2, Ti3AlC2, V0.5Cr1.5AlC, and Nb4AlC3 are 14.7 × 103, 15.5 × 103, 5.1 × 103, 8.0 × 103 S/cm, respectively, and the corresponding average EMI shielding effectiveness values in the frequency of 18–26.5 GHz are 53.9, 69.2, 19.4, and 29.0 dB, respectively. Most importantly, these MAX phases are highly corrosion resistant under acidic conditions. Despite the exposure to the acidic environment and a slight decrease in the electrical conductivity, the corroded MAX phases exhibited excellent EMI shielding properties compared to the pristine MAX phases. Additional analysis showed that reflection was the primary EMI blocking mechanism. The study offers a guide for designing MAX phase ceramics that exhibit high EMI shielding performance in corrosive environments.  相似文献   

13.
《Ceramics International》2022,48(10):13464-13474
Electromagnetic interference (EMI) shielding materials have become more and more indispensable due to serious electromagnetic-radiation pollution. Herein, waste cotton cellulose aerogels were prepared by dissolving waste cotton fabrics (WCF) in NaOH/urea aqueous solution, and MXene nanosheets were subsequently deposited on the cellulose aerogels by a facile dip coating method to obtain WCF/MXene composite aerogels. The WCF/MXene composite aerogels with highly porous network structure show remarkable electrical conductivity (8.2 Ω/sq of surface resistance), high EMI shielding effectiveness (EMI SE) in the range of 2–18 GHz (39.3–48.1 dB). The WCF/MXene aerogel possesses high SSE and SSE/t of 677.94–829.74 dB cm3 g?1 and 3512.62–4299.17 dB cm2 g?1, respectively (2–18 GHz). In addition, the heating temperature of WCF/MXene composite aerogels reaches 199 °C when 3 V positive voltage is applied on them. The WCF/MXene composite aerogels possess excellent electromagnetic shielding effectiveness, heat generation property and insulation, which can be potentially used as multifunctional materials for EMI shielding, electrical-heating and high temperature protection.  相似文献   

14.
《Ceramics International》2022,48(17):24898-24905
MXene films promise potential electromagnetic interference (EMI) shielding materials, but poor scalable processability, environmental instability, and weak mechanical properties severely restrict their applications. Herein, we engineer the large-area, high-performance, and compact nacre-like MXene-based composite films through cooperative co-assembly of Ti3C2TX MXene and reduced graphene oxide (rGO) in the presence of polyvinyl alcohol (PVA). The resulting MXene-rGO-PVA composite films benefit from enhanced bonding strength and extra chain bridging effect of linear PVA molecules enriched with hydroxyl groups. Therefore, the composite film achieves high tensile strength (~238 MPa) and toughness (~1.72 MJ m?3) while having high conductivity of ~32 S cm?1. A significant EMI shielding effectiveness (41.35 dB) is also demonstrated, with an excellent absolute shielding effectiveness of ~20,200 dB cm2 g?1 at only 12-μm thickness. Moreover, due to the synergistic effect of multiple components, the composite films maintain a stable EMI shielding performance in harsh environments (sonication, hot/cold annealing, and acid solution) with mechanical properties that fluctuate only within 10% compared to the original film. More importantly, commercial polyethylene terephthalate release liner can be applied for the film coating, facilitating continuous roll-to-roll production of large-area films and future applications.  相似文献   

15.
《Ceramics International》2022,48(8):10516-10525
Electromagnetic interference (EMI) shielding materials are receiving more and more attentions and becoming a hot research topic because of their wide range of applications in life, defense and other fields. The development of green EMI shielding materials with tunable shielding effectiveness (SE) is a high pursuit and a great challenge for researchers. Here, we restricted the growth of TiO2 on the Ti3C2Tx surface by adjusting the annealing temperature. This regulated the dipole and interface polarization and the construction of the conductive network, and improved the impedance matching. The Ti3C2Tx/TiO2 heterostructured material was rationally designed and achieved an efficient EMI SE of 35.1 dB at 18 GHz when the annealing temperature was 600 °C. This work develops new avenues for the future design of efficient, controllable green EMI shielding materials. Simultaneously, this heterostructured material has great potential as a versatile green shielding material for civil, commercial and military aerospace applications.  相似文献   

16.
A novel free radical scavenger, multi-layered Ti3C2Tx MXene (ML-Ti3C2Tx), has been studied by evaluating its scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH?). It exhibits high scavenging efficiency (95% in 10 min) at low dosage (0.06 mg/mL). Based on the analysis of structure and surface states of ML-Ti3C2Tx before and after reaction with DPPH? and a series of comparative experiments, including few-layered Ti3C2Tx MXene (FL-Ti3C2Tx), original Ti3AlC2, and soluble Ti species derived from ML-Ti3C2Tx, the observed high scavenging activity is attributed to the intrinsic reducing property of ML-Ti3C2Tx rather than the hydrogen donation ability from surface functional groups. A model is proposed to explain the scavenging mechanism.  相似文献   

17.
《Ceramics International》2022,48(16):22681-22690
Benefiting from its large specific surface area, abundant defects and functional groups, two-dimensional (2D) laminated Ti3C2Tx MXene is a kind of electromagnetic wave (EMW) absorber with great potential. However, the impedance mismatch caused by the excessive conductivity, inappropriate permittivity and lack of magnetic loss seriously hinders the application of MXene to EMW absorption. Herein, multidimensional hierarchical Ni/TiO2/C nanocomposites composed of three-dimensional (3D) hydrangea-like Ni/C microspheres and well-arranged 2D carbon sheets embedded with TiO2 nanoparticles were successfully fabricated from a Ni-based trimellitic acid framework (Ni-BTC) and Ti3C2Tx MXene via facile in-situ solvothermal assembly and annealing processes. As expected, excellent EMW absorption properties were obtained only by changing the annealing temperature. The minimum reflection loss (RLmin) value of -45.6 dB and the effective absorption bandwidth (EAB) of 3.40 GHz (14.6–18.0 GHz) with a layer thickness of only 1.5 mm is obtained by annealing the sample at 700 °C. The outstanding ternary multilayer structure and the optimization of magnetoelectric synergy in impedance matching jointly create its remarkable EMW absorption performance. This work is expected to provide a simple and effective method to design MXene-based EMW absorbing materials possessing high absorption intensity, light weight, wide EAB and thin thickness.  相似文献   

18.
《Ceramics International》2022,48(12):16892-16900
To solve pollution problems caused by electromagnetic waves, advanced three-dimensional (3D) honeycomb Ag/Ti3C2Tx hybrid materials were produced by a microwave hydrothermal method. The Ag/Ti3C2Tx hybrid materials retained their hollow sphere structure after the polymethyl methacrylate (PMMA) template was removed by annealing. The hybrid materials changed from hydrophilic to hydrophobic and exhibited cross-surface heat insulation and reflection-dominant electromagnetic interference shielding (EMIS) performance owing to their special honeycomb structure. This study innovatively explored the influence of different particle sizes of honeycomb holes on EMIS performance. In particular, the Ag/Ti3C2Tx 5 μm hybrid materials had an excellent average EMIS performance of 51.15 dB in the X-band and 56.64 dB in the Ku-band. The superior performance was due to conduction loss, interface polarization, multi-reflection, and scattering caused by the 3D porous structure of the Ag/Ti3C2Tx hybrid materials. In general, Ag/Ti3C2Tx hybrid materials with honeycomb structures retained the advantages of lightweight, hydrophobicity, and EMIS performance, illustrating the great application prospects of these materials in high-end electronic equipment.  相似文献   

19.
《Ceramics International》2022,48(17):25111-25119
Electromagnetic wave (EMW) absorbing materials have been widely applied in the fields of military and engineering areas. It is of great significance to develop high-performance EMW absorbing materials. This work assembled the sandwich-like Ti3C2Tx based nanocomposites by the microwave-assisted annealing of CoFe-MOF@Ti3C2Tx (CFMF@Ti3C2Tx) precursors at different temperatures. Results show that, as the heat treatment temperature is 450 °C, the sandwich-like Ti3C2Tx@CoFe@TiO2 nanocomposites present better EMW absorption properties. The minimum reflection loss (RL) value was ?62.9 dB at 17.95 GHz with a thin thickness of 1.2 mm. Moreover, the effective absorption bandwidth (EAB) value was 5.02 GHz (12.74–17.76 GHz) with a thickness of 1.4 mm. The application of microwave-assisted annealing contributed to the formation of CoFe nanoparticles and TiO2 nanoparticles because of the ultra-fast heating rate. The introduction of the nanoparticles enhanced the multiple polarization, optimized the impedance matching and introduced magnetic loss, leading to the improvement of EMW absorption. When the annealing temperature further increased to 550 °C, the EMW absorbing performance was weakened, which was mainly correlated with the decrement of the interface area due to the increase of the TiO2 nanoparticle size and CoFe nanoparticle size. Thus, the loss effect of the multiple interface polarization weakens in the EMW absorption. In addition, the high permittivity of Ti3C2Tx disappears, which deteriorated the impedance matching and attenuation ability of EMW. Ultimately, sandwich-like Ti3C2Tx@CoFe@TiO2 nanocomposite with satisfactory EMW absorbing properties is established, promising for various EMW absorbing applications.  相似文献   

20.
《Ceramics International》2020,46(12):20306-20312
Although the antibacterial properties of MXene nanosheets containing Ti3C2Tx are known, their antifungal properties have not been well studied. Herein, we present for the first time a report on the antifungal properties of Ti3C2Tx MXene. The Ti3C2Tx MXene was obtained by first exfoliating MAX phase of Ti3AlC2 with concentrated hydrofluoric acid, then the Ti3C2Tx was intercalated and deliminated by ethanol treatment and ultrasonication process. The delaminated Ti3C2Tx MXene nanosheets (d-Ti3C2Tx) were characterized using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX), X-ray diffraction spectroscopy (XRD), and Raman spectroscopy. It was found that Ti3C2Tx MXene was characterized by lamellar structure alternating with layers of Ti, Al and C. The EDX results revealed that the delaminated Ti3C2Tx MXene nanosheets were composed of Ti, C, Si, O, F, and a trace amount of Al. The XRD and Raman spectra further indicated the elimination of Al and the formation of two-dimensional Ti3C2Tx MXene nanosheets. The antifungal activity of the delaminated Ti3C2Tx MXene was determined against Trichoderma reesei using the modified agar disc method. Observation using inverted phase contrastmicroscopy revealed inhibited fungus growth with the absence of hyphae around the discs treated wtih MXene. The surrounding of the control groups without an inclusion of MXene was found with large number of hyphae and spores. In addition, the spores of the fungi treated with the samples containing d-Ti3C2Tx MXene nanosheets did not germinate even after 11 days of culture. The results demonstrated disruption to the hemispheric structural formation of fungi colony, inhibition of hyphae growth and cell damage for fungi grown on the d-Ti3C2Tx MXene nanosheets. These new findings suggest that d-Ti3C2Tx MXene nanosheets developed in this work could be a promising anti-fungi material.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号