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1.
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
2.
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
3.
The incorporation of nanosized pseudocapacitive materials and structure design are general strategies to enhance the electrochemical performance of MXene-based materials. Herein, the decoration of manganese dioxide (MnO 2) nanosheets on MXene (Ti 3C 2T x) surfaces was prepared by a facile liquid phase coprecipitation method. Ti 3C 2T x is initially modified by polydopamine (PDA) coating to ensure the homogeneous distribution of MnO 2 nanosheets and tight and close connections between MnO 2 and the Ti 3C 2T x backbone. Due to the obtained three-dimensional (3D) nanostructure, facilitating electron transport within the electrode and promoting electrolyte ion accessibility, the δ-MnO 2@Ti 3C 2T x-0.06 electrode yields superior electrochemical performances, such as a rather large areal capacity of 1233.1 mF cm ?2 and high specific capacitance of 337.6 F g ?1 at 2 mV s ?1, as well as high cyclic stability for 10000 cycles. Furthermore, δ-MnO 2@Ti 3C 2T x-0.06 composites are employed as positive electrodes, and activated carbon (AC) materials act as negative electrodes with an aqueous electrolyte of 1 M Na 2SO 4 to assemble asymmetric supercapacitors. The prototype device is reversible at cell voltages from 0 to 1.8 V, and manifests a maximum energy density of 31.4 Wh kg ?1 and a maximum power density of 2700 W kg ?1. These encouraging results show enormous possibilities for energy storage applications. 相似文献
4.
By combining the advantages of doping to change the electronic structure of molybdenum disulfide (MoS 2), transition metal phosphides, and MXene, we proposed the idea of designing and preparing a new type of composite material, P-doped MoS 2/Ni 2P/Ti 3C 2T x heterostructures (denoted as P@MNTC), to serve as the hydrogen evolution reaction (HER) catalyst of electrochemical water splitting. The as-prepared P@MNTC heterostructures show a significant HER activity with an overpotential of 120 mV at 10 mA cm –2 in alkaline electrolyte, with decreasing 105 and 125 mV compared with those of MoS 2 and MXene, respectively. The density functional theory indicates that the P doping and synergy effect of Ti 3C 2T x can enhance the activation of MoS 2 and thus promote dissociation and absorption of H 2O during HER process. This strategy provides a promising way to develop high-efficiency MoS 2- and Ti 3C 2T x-based composite catalysts for alkaline HER. 相似文献
5.
Since conventional Pt/carbon catalysts usually suffer from CO poisoning as well as carbon corrosion issues during the methanol oxidation reaction, it is essential to explore high-efficiency Pt-alternative electrocatalysts supported by a robust matrix in the direct methanol fuel cells. Herein, we report a convenient low-temperature approach to the controllable fabrication of well-dispersive Rh nanocrystals in situ grown on Ti 3C 2T x MXene nanosheets. The ultrathin lamellar MXene structure reveals unique superiorities on the construction of advanced Rh-based hybrid catalysts, which can not only provide a large number of efficient anchoring sites for immobilizing small-sized Rh nanocrystals with abundant exposed catalytic crystal planes, but also enable direct electronic interaction with Rh for strong synergistic effects and facilitate the fast charge transportation during the catalytic process. As a consequence, the resulting Rh/Ti 3C 2T x hybrid exhibits prominent electrocatalytic properties towards methanol oxidation reaction, such as a large electrochemical active surface area of 71.6 m 2 g ?1, a high mass activity of 600.2 mA mg ?1, and good long-term stability, all of which are much better than those of conventional carbon-supported Rh as well as Pt/C and Pd/C catalysts. 相似文献
6.
Two-dimensional transition metal carbide (MXene) is a promising electrode material for supercapacitors because of its excellent electrochemical properties. Here, we report a controllable and facile strategy to prepare a freestanding and flexible N-doped Ti 3C 2T x (N–Ti 3C 2T x) film electrode with a hydrothermal method using hydrazine hydrate (N 2H 4∙H 2O) as a nitrogen source. At a scan rate of 2 mV s −1, the N–Ti 3C 2T x film electrode exhibits a high specific capacitance of 340 F g −1 and no capacitance degradation after 10,000 cycles in 1 M H 2SO 4 electrolyte. These results show that the N–Ti 3C 2T x film could be used as an outstanding electrode material for high-performance supercapacitors. The operation of hydrazine treatment provides a more practical and convenient experimental method for N-doping. 相似文献
7.
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
8.
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
9.
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
10.
With the expanding range of applications for lithium-ion batteries, a great deal of research is being conducted to improve their capacity, stability, and charge/discharge rates. This study was performed to investigate the effects of MXene, which has a large surface area and metallic conductivity, as a conductive additive to the cathode, on electrochemical performance. The two-dimensional material MXene constructs a conductive network with zero-dimensional carbon black in plane-to-point mode to improve conductivity and contact area with active materials, thereby facilitating fast charge transfer. The conductive network reduces the internal resistance and polarization of the cathode and aids the diffusion of electrons. The electrode containing an appropriate amount of MXene showed improved rate performance, high discharge capacity (123.9 mAh g −1 at 4 C), and excellent cycle stability at a high scan rate (125.8 mAh g −1 at 2 C after 150 cycles) compared to pristine electrodes. Based on these results, Ti 3C 2T x MXene is a promising conductive additive in the battery field. 相似文献
11.
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
12.
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
13.
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
14.
Ti 3C 2T x MXene has attracted remarkable attention due to its promising applications in energy storage and sensors. However, traditional MXene preparation methods used HF as etchant, which was highly toxic and harmful to human and environment. Moreover, the aqueous etchants will also result in the combination of OH, O and F groups on the surfaces, making it difficult to control the varieties and contents of the surface terminations. In this paper, a green and mild electrochemical exfoliation method was proposed to synthesize Ti 3C 2F x and synchronously control its fluorination degree on the surface. A non-aqueous ionic liquid, [BMIM][PF 6]-based solution was used as electrolyte. The as-prepared Ti 3C 2F x was fluorinated with the CF and TiF 3 groups, which were electrochemically active and contributed to the excellent cycling stability of the MXene anode-based Li-ion batteries. These findings provided a facile strategy to prepare MXene materials and dope MXene with tailored property for MXene-based energy devices applications. 相似文献
15.
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
16.
As one of the novel two-dimensional metal carbides, Ti 3C 2T x has received intense attention for lithium-ion batteries. However, Ti 3C 2T x has low intrinsic capacity due to the fact that the surface functionalization of F and OH blocks Li ion transport. Herein a novel “plane-line-plane” three-dimensional (3D) nanostructure is designed and created by introducing the carbon nanotubes (CNTs) and SnO 2 nanoparticles to Ti 3C 2T x via a simple hydrothermal method. Due to the capacitance contribution of SnO 2 as well as the buffer role of CNTs, the as-fabricated sandwich-like CNTs@SnO 2/Ti 3C 2T x nanocomposite shows high lithium ion storage capabilities, excellent rate capability and superior cyclic stability. The galvanostatic electrochemical measurements indicate that the nanocomposite exhibits a superior capacity of 604.1 mAh g ?1 at 0.05?A?g ?1, which is higher than that of raw Ti 3C 2T x (404.9 mAh g ?1). Even at 3?A?g ?1, it retains a stable capacity (91.7 mAh g ?1). This capacity is almost 5.6 times higher than that of Ti 3C 2T x (16.6 mAh g ?1) and 58 times higher than that of SnO 2/Ti 3C 2T x (1.6 mAh g ?1). Additionally, the capacity of CNTs@SnO 2/Ti 3C 2T x for the 50th cycle is 180.1 mAh g ?1 at 0.5?A?g ?1, also higher than that of Ti 3C 2T x (117.2 mAh g ?1) and SnO 2/Ti 3C 2T x (65.8 mAh g ?1), respectively. 相似文献
17.
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
18.
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
19.
In this paper, Gd 3+ doped V 2O 5/Ti 3C 2T x MXene (GVO/MX) hierarchical architectures have been synthesized by wet chemical approach. As prepared GVO/MX composite, along undoped VO and unsupported GVO were well characterized by XRD, FESEM, EDX, FT-IR and BET techniques. Electrochemical performance of VO, GVO and GVO/MX was evaluated by CV, GCD and EIS measurements. Among the three electrodes, GVO/MX composite exhibited highest electrochemical activity with the optimum specific capacitance of 1024 Fg -1 at 10 mVs ?1. The specific capacitance of GVO/MX was ~1.7 and ~3 times higher than unsupported GVO (585 Fg -1) and VO (326 Fg -1), respectively. The cyclic life of GVO/MX with capacitance retention 96.12% was observed at 60 mVs ?1. EIS measurements showed reduction in electrochemical impedance for GVO/MX as compared to GVO and VO. The corresponding impedance values of Rct and Resr for GVO/MX were calculated as 18 Ω and 1.8 Ω, respectively. The superior capacitive ability of GVO/MX can be ascribed to its unique morphology, short diffusion path and high surface area of fabricated composite. Considering it, the present work provides a feasible strategy to fabricate highly effective electrode materials for next generation energy storage devices. 相似文献
20.
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
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