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1.
Ti 3C 2T x MXene, an emerging two-dimensional (2D) ceramic material, has rich interfaces and strong conductive networks. Herein, we have successfully built a heterostructure between Ti 3C 2T x MXene and WS 2 to improve electromagnetic absorption performance. X-ray diffraction and X-ray photoelectron spectroscopy were used to determine the successful synthesis of Ti 3C 2T x/WS 2 composite. Field emission scanning electron microscopy and transmission electron microscopy images show that WS 2 nanosheets are evenly dispersed on the accordion-like Ti 3C 2T x MXene. Importantly, Ti 3C 2T x MXene/WS 2 composite has sufficiently high dielectric loss and impedance matching due to self-adjusting conductivity and 2D heterostructure interfaces. As a result, the Ti 3C 2T x/WS 2 composite has a minimum reflection loss (RL min) 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 Ti 3C 2T x ceramics and 2D materials. 相似文献
2.
Different kinds of two-dimensional hybrid electrodes have high theoretical capacitance and energy density. However, the origin of the electrochemical storage mechanism still remains elusive in alkaline, acid and neutral electrolytes. Herein, the interstratification-assembled Ti 3C 2T x MXene/NiCo-LDHs electrodes were successfully prepared and studied in different electrolytes by in-situ Raman spectroscopy. The results show that H 2O molecules in neutral electrolyte combine with –OH at the end of Ti 3C 2T x MXene during charging, and debonding occurs during discharge. Similarly, this reaction also occurs in the discharge process with NiCo-LDHs and provides smaller pseudocapacitance characteristics. Although this pseudocapacitance reaction also occurs in acidic and alkaline electrolytes, however, the difference is that the hydrogen ions will promote the electrochemical performance of Ti 3C 2T x MXene and has a certain corrosion consumption effect on NiCo-LDHs, but generally improve the electrochemical performance of Ti 3C 2T x MXene/NiCo-LDHs. Interestingly, the OH ? in alkaline electrolyte can promote the electrochemical performance of NiCo-LDHs, and produce a new electrochemical reaction with –F between the layers of Ti 3C 2T x MXene, which greatly improves the overall electrochemical performance of this hybrid electrodes. As a result, Ti 3C 2T x MXene/NiCo-LDHs electrodes have the best electrochemical performance in alkaline electrolyte with capacitance of 283 F g ?1, energy density of 14.2 Wh kg ?1 and power density of 3007.1 W kg ?1. This work lays a foundation for the preparation of high-performance two-dimensional hybrid electrochemical energy storage devices. 相似文献
3.
Highly active two-dimensional (2D) nanocomposites have been widely concerned in the field of gas sensors because of their unique advantages and synergistic effects. 2D/2D SnO 2 nanosheets/Ti 3C 2T x MXene nanocomposites were synthesized by using layered Ti 3C 2T x MXene and uniform SnO 2 nanosheets by hydrothermal method. Characterization results show that the SnO 2 nanosheets are well dispersed and vertically anchored on the layered Ti 3C 2T x MXene surface, forming heterogeneous interfaces. Based on the gas-adsorption capabilities and synergistic effects of electronic properties, SnO 2 nanosheets/Ti 3C 2T x MXene nanocomposites show high triethylamine (TEA) gas-sensing performance at low temperature (140 °C). The sensor responses of the nanocomposites and pure SnO 2 nanosheets to 50 ppm of TEA are 33.9 and 3.4, respectively. An enhancement mechanism for SnO 2 nanosheets/Ti 3C 2T x MXene nanocomposites is proposed for highly sensitive and selective detection of TEA at low temperature. The combination strategy of two-dimensional metal oxide semiconductor and multilayer MXene provides a new way for the development of cryogenic gas sensors in the future. 相似文献
4.
The few-layered Ti 3C 2T x/WO 3 nanorods foam composite material was synthesized by electrostatic self-assembly and bidirectional freeze-drying technologies. The phase structure and microstructure of synthesized samples was characterized by XRD, FESEM, TEM and their gas sensing properties estimated via a self-designed equipment with four test channels. The results demonstrate WO 3 nanorods were successfully anchored on the surface and between layers of few-layered Ti 3C 2T x MXene by electrostatic self-assembly strategy and the composite material simultaneously has a low-density foam morphology by means of bidirectional freeze-drying processes. There exists a typical heterostructure at the interfaces owing to the inseparable contact between the few-layered Ti 3C 2T x MXene and WO 3 nanorods. Compared with the original WO 3 nanorods, the few-layered Ti 3C 2T x/WO 3 nanorods foam composite material displays excellent gas sensing properties for NO 2 detection at low temperature, in particular the optimal value of gas sensing response ( Rg/Ra) reaches to 89.46 toward 20 ppm NO 2 at 200 °C. The gas sensing mechanism was also discussed. The increase of gas sensitivity is attributed to a fact that during the reaction process of gas sensing, the excellent conductivity of the few-layered Ti 3C 2T x MXene provided faster transport channels of free carriers, and the heterojunctions formed by few-layered Ti 3C 2T x MXene and WO 3 nanorods enhanced the carriers separation efficiency. Meanwhile, the low-density layered structure of few-layered Ti 3C 2T x/WO 3 nanorods foam composite material provides convenient diffusion paths for gas molecules to the surface of WO 3 nanorods. 相似文献
5.
Ti 3C 2T x exhibits excellent electromagnetic (EM) shielding and electrochemical properties. However, the inherent re-stacking tendency and easy oxidation of Ti 3C 2T x limit its further application. In this study, a multi-walled carbon nanotube/polyaniline composite (CNT/PANI, denoted as C–P) was introduced into Ti 3C 2T x nanosheets to obtain a Ti 3C 2T x–CNT/PANI composite (T@CP). Owing to the integrated effects of Ti 3C 2T x 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 Ti 3C 2T x (45.3 dB). Moreover, T@CP demonstrated outstanding supercapacitive performance. The specific capacitance of T@CP (2134.5 mF/cm 2 at 2 mV/s) was considerably higher than that of pure Ti 3C 2T x (414.3 mF/cm 2 at 2 mV/s). These findings provide a new route for the development of high-efficiency Ti 3C 2T x-based bifunctional EM shielding and electrochemical materials. 相似文献
6.
Developing a new strategy to effectively prevent the restacking of MXene nanosheets will have significant impacts on designing flexible supercapacitor electrodes. Herein, a novel Ti 3C 2T x/polyvinyl alcohol (PVA) porous sponge with 3D interconnected structures is prepared by sol-gel and freeze-dried methods. This Ti 3C 2T x/PVA porous sponge is used as the template of in-situ polyaniline (PANI) polymerization, and the fabricated PANI@Ti 3C 2T x/PVA hydrogel composite is applied as flexible supercapacitors electrodes. 1D conductive polymer chains PVA could increase the interlayer spacing of Ti 3C 2T x nanosheets, which is beneficial to expose more electrochemical active sites. The supercapacitor based on PANI@Ti 3C 2T x/PVA hydrogel composite exhibits the coexistence of double-layer capacitance and pseudocapacitance behavior. This supercapacitor shows a maximum areal specific capacitance of 103.8 mF cm ?2 at 2 A m ?2, and it also exhibits a maximum energy density of 9.2 μWh·cm ?2 and an optimum power density of 800 μW cm ?2. The capacitance of this supercapacitor is almost not change under different bending angles. Moreover, 99% capacitance retention is achieved after 10 000 charge/discharge cycles of the supercapacitor. The synergistic effect between PANI and Ti 3C 2T x/PVA composite may improve the number of reactive sites and provide efficient channels for ion diffusion/electron transport. 相似文献
7.
Two-dimensional layered Ti 3C 2T x MXene was prepared through hydrothermal etching method with LiF and hydrochloric (HCl) acid. Ti 3C 2T x was further treated with oxygen plasma activated by microwave energy to obtain the activated Ti 3C 2T x at different temperatures ranging from 350 °C to 550 °C. The gas-sensing properties of raw Ti 3C 2T x and Ti 3C 2T x activated with oxygen microwave plasma were tested toward different volatile organic compounds gases. The results indicated that Ti 3C 2T x activated at 500 °C exhibited excellent gas-sensing properties at room temperature (25 °C) to 100 ppm ethanol with a value of 22.47, which is attributed to the enhancement of the amount of oxygen functional groups and defects on the MXene Ti 3C 2T x film, and in turn to lead to more oxygen molecules adsorption and desorption reaction in the active defect sites. The enhancement of ethanol-sensing performance demonstrated that the activated Ti 3C 2T x possess great potential in gas sensing. 相似文献
8.
Highly active two-dimensional (2D) nanocomposites, integrating the unique merits of individual components and synergistic effects of composites, have been recently receiving attention for gas sensing. In this work, In 2O 3 nanocubes/Ti 3C 2T x MXene nanocomposites were synthesized using In 2O 3 nanocubes and layered Ti 3C 2T x MXene via a facile hydrothermal self-assembly method. Characterization results indicated that the In 2O 3 nanocubes with sizes approximately 20–130 nm in width were well dispersed on the surface of layered Ti 3C 2T x MXene to form numerous heterostructure interfaces. Based on the synergistic effects of electronic properties and gas-adsorption capabilities, In 2O 3 nanocubes/Ti 3C 2Tx MXene nanocomposites exhibited high response (29.6%–5 ppm) and prominent selectivity to methanol at room temperature. Meanwhile, the low detection concentration could be reduced to ppm-level, the response/recovery times are shortened to 6.5/3.5 s, excellent linearity and outstanding repeatability. The strategy of compositing layered MXene with metal oxide semiconductor provides a novel pathway for the future development of room temperature gas sensors. 相似文献
9.
A novel free radical scavenger, multi-layered Ti 3C 2T x MXene (ML-Ti 3C 2T x), 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-Ti 3C 2T x before and after reaction with DPPH? and a series of comparative experiments, including few-layered Ti 3C 2T x MXene (FL-Ti 3C 2T x), original Ti 3AlC 2, and soluble Ti species derived from ML-Ti 3C 2T x, the observed high scavenging activity is attributed to the intrinsic reducing property of ML-Ti 3C 2T x rather than the hydrogen donation ability from surface functional groups. A model is proposed to explain the scavenging mechanism. 相似文献
10.
Although the antibacterial properties of MXene nanosheets containing Ti 3C 2T x are known, their antifungal properties have not been well studied. Herein, we present for the first time a report on the antifungal properties of Ti 3C 2T x MXene. The Ti 3C 2T x MXene was obtained by first exfoliating MAX phase of Ti 3AlC 2 with concentrated hydrofluoric acid, then the Ti 3C 2T x was intercalated and deliminated by ethanol treatment and ultrasonication process. The delaminated Ti 3C 2T x MXene nanosheets (d-Ti 3C 2Tx) 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 Ti 3C 2T x MXene was characterized by lamellar structure alternating with layers of Ti, Al and C. The EDX results revealed that the delaminated Ti 3C 2T x 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 Ti 3C 2T x MXene nanosheets. The antifungal activity of the delaminated Ti 3C 2T x 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-Ti 3C 2T x 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-Ti 3C 2T x MXene nanosheets. These new findings suggest that d-Ti 3C 2T x MXene nanosheets developed in this work could be a promising anti-fungi material. 相似文献
11.
Dielectric polymer composites with conducting fillers would have great potential for diverse applications if their severe leakage loss could be addressed. In this regard, ternary composites using both ceramic and conducting materials as fillers might be an enabler for high dielectric constant and low dielectric loss. Herein, ternary composites with both Ti 3C 2T x MXene conducting nanosheets and CaCu 3Ti 4O 12 (CCTO) dielectric particles embedded in silicone rubber were studied. It was found that a ternary composite with 1.2 wt% (0.40 vol%) Ti 3C 2T x MXene and 12 wt% (2.58 vol%) CCTO could provide an overall superior performance that include a high dielectric constant of 8.8, low dielectric loss of less than 0.0015, good thermal stability up to 450 °C, and excellent mechanical properties with tensile strength of 569 kPa, elastic module of 523 kPa and elongation at break of 333%. The outstanding performance is attributed to the improved uniform dispersion and good interfacial compatibility of mixed fillers in the polymer matrix, suggesting ternary composites might be a better option over their binary counterparts in preparing high performance dielectric composites. 相似文献
12.
Ti 3C 2T x MXene has attracted extensive attention in the field of electromagnetic (EM) protection over recent years. Multilayer Ti 3C 2T x (M-Ti 3C 2T x), as an intermediate product of MXene ultra-thin structure, has potential advantages in the field of EM protection. Herein, the M-Ti 3C 2T x was obtained by HCl/LiF etching Ti 3AlC 2. The microwave absorption (MA) and electromagnetic interference (EMI) shielding performance of Ti 3AlC 2 and M-Ti 3C 2T x were compared. The mechanism research of MA and EMI shielding indicates that the construction of local conductive network plays a leading role in the EM wave attenuation. The sample with 30% M-Ti 3C 2T x display RL min of ?50.26 dB, and corresponding bandwidth of 4.64 GHz at the thickness of 1.7 mm. Especially, the metastructure based on the EM parameters of M-Ti 3C 2T x/wax exhibits ultra-wide bandwidth (15.54 GHz). Our research will provide a basis for the design of MXene-based EM protection performance. 相似文献
13.
Most of the ancient buildings are made of inflammable wooden structures, which have serious potential safety hazards. Applying fire-retardant coating is one of the simplest and most effective means of fire prevention in ancient wooden buildings. In this work, we have demonstrated that the Ti 3C 2T x transition metal carbide/carbonitride (MXene) was applied as the synergetic agent, waterborne epoxy resin as the film-forming agent, ammonium polyphosphate, dipentaerythritol, and melamine (P-C-N system) as the intumescent fire-retardant system to prepare Ti 3C 2T x/epoxy intumescent fire-retardant coating (TEIFC). The results showed that MXene has significantly improved the fire-retardant performance of the coating. By incorporating 3 wt% Ti 3C 2T x (TEIFC-3, with 62 wt% P-C-N system), the coating displayed UL-94 V-0 rating with the limiting oxygen index value of 38%. In addition, the combination of Ti 3C 2T x and P-C-N system enhanced the Shore hardness of the coating to 95 SHD (TEIFC-3). Furthermore, TEIFC-3 presented high thermal stability with the THRI of 177.0°C and Tdmax of 380.5°C. This work provides a novel strategy for the design and preparation of intumescent fire-retardant coating, which will greatly broaden the industrial applications of MXene-based polymer composites in the field of fire prevention of ancient buildings. 相似文献
14.
In order to obtain a high photoelectrochemical performance, co-catalysts loading is the most commonly used way, which can facilitate reactions and suppress the charge recombination. In this paper, a novel composite of ZnO/Ti3C2TX photoanode was fabricated by a facile spin coating of precipitating Ti3C2TX (MXene) flakes onto the surface of ZnO, as co-catalyst for enhanced photoelectrochemical (PEC) water splitting. Under simulated sunlight, the optimum composite of ZnO/Ti3C2TX photoanode showed the photocurrent density as 1.2 mA cm?2 at 1.23 VRHE, which is 1.4 times higher than that of pristine ZnO without Ti3C2TX co-catalyst (0.83 mA cm?2 at 1.23 VRHE). The ZnO/Ti3C2TX photoanode showed a photoconversion efficiency of 0.32% and maintained a stable photocurrent over 2000s. The Ti3C2TX (MXene) flakes as co-catalyst to promote the charge transfer and accelerates the reaction kinetics in ZnO/Ti3C2TX photoanode. This work delivers a two-dimensional (2D) material Ti3C2TX (MXene) as co-catalyst for enhanced ZnO photoanode PEC water splitting. 相似文献
15.
As one of the typical MXenes materials, 2D Ti 3C 2T x has attracted extensive attention in the field of energy storage. However, due to the restacking problem of Ti 3C 2T x nanosheets, the electrochemical performance of Ti 3C 2T x is unsatisfactory. In this paper, a scheme is proposed to obtain 3D aerogel with 1D channels by directional freeze drying of Ti 3C 2T x. With the help of the unidirectional channels, the 3D Ti 3C 2T x/Sodium alginate (SA) aerogel can effectively solve the stacking problem of Ti 3C 2T x nanosheets, and it also accelerates the diffusion of ions. The Ti 3C 2T x/SA-5 electrode can still reach the mass capacitance of 284.5 F g ?1 and the areal capacitance of 4030.4 mF cm ?2 at 2 mV s ?1 when the loading is 14.2 mg cm ?2 in 1 M H 2SO 4 electrolyte. In addition, the electrode showed good cycling performance without capacitor degradation after 20,000 cycles at 50 mV s ?1. These results suggest that by using the strategy of building special 3D structure of 2D MXene with 1D unidirectional channels, high performance supercapacitor electrodes with high mass loading can be realized. 相似文献
16.
Ti 3C 2T x MXene has been reported to be a metallic two-dimensional (2D) material with high conductivity, whereas its photoluminescence (PL) mechanism is still under debate. Herein, we demonstrate that large Ti 3C 2T x MXene flakes exhibit tunable PL under ambient conditions. The as-prepared Ti 3C 2T x MXene flakes emit blue, yellow-green and red light under different excitation wavelengths. Their PL emission wavelengths redshift as the excitation wavelength changes from violet to red light. Surface modification of the MXenes can further tune the PL peak wavelength into the near infrared region. Using density function theory (DFT) calculations, this excitation wavelength-dependent PL can be correlated to TiO 2 defects that exist on the surface of Ti 3C 2T x. Our study expounds on the optical properties of Ti 3C 2T x MXene and is helpful for comprehensively understanding this novel material. 相似文献
17.
Three-dimensional flower-like Ni(NiO) decorated on two-dimensional Ti 3C 2T x/TiO 2 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)/Ti 3C 2T x/TiO 2 composites include flower-like Ni(NiO) with uniform distribution on the surface of Ti 3C 2T x MXenes and part of them get into the space between interlayers. The Ni(NiO)/Ti 3C 2T x/TiO 2 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 Ti 3C 2T x 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 Ti 3C 2T x 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)/Ti 3C 2T x/TiO 2 composites a hopeful material for microwave absorption (MA). 相似文献
18.
MXene, a novel two-dimensional material composed of alternating transition metal carbon/nitrogen, has the advantages of large specific surface area, many active sites, and short ion transport paths, and has shown great potential in the field of capacitors in the beginning. However, the unique two-dimensional structure is prone to collapse and accumulation, which inhibits the electron migration rate and ion penetration, resulting in poor energy storage capacity. In this paper, Ti 3C 2T x/Ag/MWCNTs/Ag composites with good capacitive properties were successfully prepared by Ti 3C 2T x which directly reduces silver nitrate solution and further introduces nanoscale MWCNTs. Ag NPs are introduced twice to grow and distribute uniformly on the surface and between the layers of Ti 3C 2T x to play a supporting role. The introduction of MWCNTs in the intermediate process can enter the interlayer and act as spacers together with Ag NPs to prevent the collapse and stacking of Ti 3C 2T x and improve its surface utilization. However, the preparation process unavoidably leads to partial oxidation of Ti 3C 2T x, which deteriorates its electrochemical properties. Owing to the synergy between Ti 3C 2T x, Ag NPs and MWCNTs, the Ti 3C 2T x/Ag/MWCNTs/Ag composites show good electrical conductivity, low internal resistance (0.67 Ω) and extreme high capacitance contribution (97%) in electrochemical tests. 相似文献
19.
In this work, TiO 2/MXene composites were successfully synthesized through an in-situ solvothermal method, where the morphology of TiO 2 nanoparticles (NPs) was modified by different concentrations of agents. Ti 3C 2T x with electronic storage characteristics was employed as a co-catalyst to enhance the photocatalytic degradation activity by capturing photogenerated electrons. The experimental results reveal that, with the help of C 3H 8O agents, TiO 2 NPs are uniformly distributed on the surface of Ti 3C 2T x. The TiO 2/Ti 3C 2T x-C 3H 8O composite showed the highest photocatalytic activity of 90.5% after 75 min under mercury light irradiation, which is 57.9% higher than that of the pure TiO 2 photocatalyst. The photocatalytic activity is promoted due to the high photoelectron transmission performance of the TiO 2/Ti 3C 2T x composites. 相似文献
20.
To prevent restacking of the Ti 3C 2T x layers, the Ti 3C 2T x-foam has been successfully synthesized through thermal treatment of Ti 3C 2T x-film with the hydrazine monohydrate. The interconnected porous structure of Ti 3C 2T x-foam could effectively reduce the restacking of the Ti 3C 2T x sheets and shorten the diffusion path of ions and accelerate the intercalation/de-intercalation of ions. The Ti 3C 2T x-foam-80 used as free-standing electrode achieves a high areal capacitance of 271.2 mF/cm 2 (122.7?F/g) at a scan rate of 5?mV/s in 1?M KOH electrolyte. It also exhibited a high capability rate of 65.5% from 5?mV/s to 100?mV/s and good cycle life with 88.7% retention of its initial after 10,000 cycles at a scan rate of 50?mV/s. 相似文献
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