Titanium Carbide Nanosheets Research Articles

Engineering MXene surface with POSS for reducing fire hazards of polystyrene with enhanced thermal stability

High-performance MXene-based polymer nanocomposites are highly desirable for diverse industry applications due to their exceptional mechanical, thermal and other properties. Nevertheless, it remains an intractable challenge to create flame retardant polymer/MXene nanocomposites due to the difficulty to achieve uniform dispersion of MXenes. Here, we reported a facile strategy for the surface manipulation of two-dimensional titanium carbide nanosheets (Ti3C2Tx) with 3-aminopropylheptaisobutyl-polyhedral oligomeric silsesquioxane (AP-POSS) (POSS-Ti3C2Tx) through electrostatic interactions. The POSS-Ti3C2Tx is steadily dispersed in many polar solvents. Upon incorporated into polystyrene (PS), the combined effect of AP-POSS and MXene makes the resultant PS nanocomposites exhibit significantly improved thermal and thermoxidative stability, e.g. 22 °C and 39 °C increases in the temperature at 5 wt% mass loss under nitrogen and air, respectively. Meanwhile, a 39.1 % reduction in the peak heat release rate, a respective 54.4 % and 35.6 % reduction in the peak CO production rate and the peak CO2 production rate was achieved, which are superior to those of its own and previous counterparts. This outstanding fire safety is attributed to the combination of adsorption, catalytic and barrier effects of POSS-Ti3C2Tx. Hence, as-designed functionalized MXenes can be effectively applied in PS to formulate multifunctional polymer nanocomposites attractive for wide potential applications.

Nanocomposites induced by two-dimensional titanium carbide nanosheets for highly efficient energy storage

Surface group-rich titanium carbide nanosheets (TCNSs) were successfully fabricated by simply etching Ti3AlC2 powders and used as dielectric fillers to promote the dielectric and energy storage performances of poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP)-based composites. The PVDF-HFP/TCNS composites realize a high dielectric constant and low dielectric loss of 16.3 and 0.034 at 102 Hz, respectively. Importantly, a high energy storage density (Ue) of 0.367 J cm−3 at 900 kV cm−1 and a high energy storage efficiency (η ≥ 78.9%) at a TCNS content of only 0.5 wt% are obtained, which indicates that incorporating TCNS is an efficient route in enhancing Ue while maintaining a high level η of the PVDF-HFP-based composites. According to detailed characterization results, a mechanism related to the reduction of lamellar crystals in the PVDF-HFP matrix is suggested. The above mechanism restricts the movement of polymer chains near the filler-matrix interface and is proposed to be responsible for the outstanding dielectric and energy storage performances. Consequently, this work provides a simple and effective method for fabricating highly efficient energy storage nanocomposites.

Interface engineering of MXene towards super-tough and strong polymer nanocomposites with high ductility and excellent fire safety

The integration of high strength, high toughness, and excellent flame retardancy in polymer materials is highly desirable for their practical applications in the industry. However, existing material design strategies often fail to realize such a performance portfolio because of mutually exclusive mechanisms between strength and toughness, and low flame retardancy efficiency of nanofillers in polymers. Here, we reported the preparation of a multifunctional nanohybrid, Ti3C2Tx@MCA, by engineering the surface of titanium carbide nanosheets (Ti3C2Tx, MXene) with melamine cyanurate (MCA) via hydrogen bonding interactions, and subsequent thermoplastic polyurethane (TPU)/Ti3C2Tx@MCA nanocomposites. The resultant TPU nanocomposite containing 3.0 wt% of Ti3C2Tx@MCA shows a high tensile strength of 61.5 MPa, a toughness as high as 175.4 ± 7.9 MJ m−3 and a high strain at failure of 588%, and 40% reduction in the peak of heat release rate. Such extraordinary mechanical and fire retardant performances are superior to those of its previous counterparts. Interfacial hydrogen bonding in combination with the “labyrinth” effect and catalytic action of 2D Ti3C2Tx nanosheets are responsible for the outstanding mechanical and fire retardancy properties of TPU nanocomposites. This work provides a new paradigm for integral design of high-performance polymeric materials with excellent mechanical and fire-safe performances portfolio.

Antibiotics Separation with MXene Membranes Based on Regularly Stacked High-Aspect-Ratio Nanosheets.

The uncontrolled release of antibiotics and pharmaceuticals into the environment is a worldwide increasing problem. Thus, highly efficient treatment technologies for wastewater are urgently needed. In this work, seven kinds of typical antibiotics (including water and alcohol soluble ones) are successfully separated from the corresponding aqueous and ethanolic solutions using highly regular laminated membranes. Our membranes are assembled with 2-4 μm titanium carbide nanosheets. The solvent permeance through such titanium carbide membrane is one order of magnitude higher than that through most polymeric nanofiltration membranes with similar antibiotics rejection. This high flux is due to the regular two-dimensional (2D) structure resulting from the large aspect ratio of titanium carbide nanosheets. Moreover, the electrostatic interaction between the surface terminations and the antibiotics also affects the rejection and enhances the antifouling property. Such 2D titanium carbide membranes further broaden the application scope of laminated materials for separation and purification of high value added drugs in academia and industry.

Antibiotics Separation with MXene Membranes Based on Regularly Stacked High‐Aspect‐Ratio Nanosheets

AbstractThe uncontrolled release of antibiotics and pharmaceuticals into the environment is a worldwide increasing problem. Thus, highly efficient treatment technologies for wastewater are urgently needed. In this work, seven kinds of typical antibiotics (including water and alcohol soluble ones) are successfully separated from the corresponding aqueous and ethanolic solutions using highly regular laminated membranes. Our membranes are assembled with 2–4 μm titanium carbide nanosheets. The solvent permeance through such titanium carbide membrane is one order of magnitude higher than that through most polymeric nanofiltration membranes with similar antibiotics rejection. This high flux is due to the regular two‐dimensional (2D) structure resulting from the large aspect ratio of titanium carbide nanosheets. Moreover, the electrostatic interaction between the surface terminations and the antibiotics also affects the rejection and enhances the antifouling property. Such 2D titanium carbide membranes further broaden the application scope of laminated materials for separation and purification of high value added drugs in academia and industry.

Compressible, Elastic, and Pressure-Sensitive Carbon Aerogels Derived from 2D Titanium Carbide Nanosheets and Bacterial Cellulose for Wearable Sensors

Compressible and elastic carbon aerogels (CECAs) hold great promise for applications in wearable electronics and electronic skins. MXenes, as new two-dimensional materials with extraordinary proper...

Mechanically strong and electrically conductive multilayer MXene nanocomposites.

Polymer nanocomposites offer the opportunity to bridge properties of nanomaterials to the macroscale. In this work, layer-by-layer (LbL) assembly is used to demonstrate nanocomposites of 2D titanium carbide nanosheets (MXene) and clay nanoplatelets (montmorillonite) to fabricate freestanding thin films with unique multifunctional properties. These thin films can be tuned by adjusting the thickness to exhibit a tensile strength of 138 MPa-225 MPa, EMI specific shielding effectiveness normalized to thickness and density up to 24 550 dB cm2 g-1, and sheet resistance from 855 Ω sq-1-3.27 kΩ sq-1 (corresponding to a range of conductivity from 53 S m-1 to 125 S m-1). This composite is the strongest MXene-based LbL film prepared to date, in part due to the nacre-like brick-and-mortar structure. Ultra-strong, multifunctional films of this nature are desirable for many applications ranging from membranes, to structural and multifunctional composites, energy harvesting and storage, and materials for aerospace.

Phospholipid-Tailored Titanium Carbide Nanosheets as a Novel Fluorescent Nanoprobe for Activity Assay and Imaging of Phospholipase D.

As one of the emerging inorganic graphene analogues, two-dimensional titanium carbide (Ti3C2) nanosheets have attracted extensive attention in recent years because of their remarkable structural and electronic properties. Herein, a sensitive and selective nanoprobe to fluorescently probe phospholipase D activity was developed on the basis of an ultrathin Ti3C2 nanosheets-mediated fluorescence quenching effect. Ultrathin Ti3C2 nanosheets with ∼1.3 nm in thickness were synthesized from bulk Ti3AlC2 powder by a two-step exfoliation procedure and further modified by a natural phospholipid that is doped with rhodamine B-labeled phospholipid (RhB-PL-Ti3C2). The close proximity between RhB and Ti3C2 leads to efficient fluorescence quenching (>95%) of RhB by energy transfer. Phospholipase D-catalyzed lipolysis of the phosphodiester bond in RhB-PL results in RhB moving away from the surface of Ti3C2 nanosheets and subsequent fluorescence recovery of RhB, providing a fluorescent "switch-on" assay for the phospholipase D activity. The proposed nanoprobe was successfully applied to quantitatively determine phospholipase D activity with a low limit of detection (0.10 U L-1) and to measure its inhibition. Moreover, in situ monitoring and imaging the activity of phospholipase D in living cells were achieved using this biocompatible nanoprobe. These results reveal that Ti3C2 nanosheets-based probes exhibit great potential in fluorometric assay and clinical diagnostic applications.

Synergistically enhanced lithium storage performance based on titanium carbide nanosheets (MXene) backbone and SnO2 quantum dots

Titanium carbide MXene (Ti3C2Tx) possesses a metallic conductivity and an opened nanostructure, being an ideal host for transition metal oxide (TMO) to construct advanced lithium-ion battery anodes. However, Ti3C2Tx is prone to be oxidized under hydrothermal treatment, which limits the growth of TMO/MXene composites through a wet-chemistry approach. Here, we take advantage of the strong electrostatic interaction between SnO2 quantum dots (QDs) and delaminated Ti3C2Tx to protect the latter from oxidation under the hydrothermal condition. The in-situ heterogeneously nucleated SnO2 QDs are tightly anchored on the Ti3C2Tx nanosheets, while the Ti3C2Tx nanosheets effectively limit the growth/aggregation of SnO2. Further freeze-drying of the colloidal mixture results in the SnO2 QDs@Ti3C2Tx composite with conductive Ti3C2Tx nanosheets as backbone, which displays a high specific surface area and abundant voids. The unique architecture design renders SnO2 QDs@Ti3C2Tx a high capacity (1021 mAh g−1 at 100 mA g−1 in the 2.6 mg cm−2 electrode) and long lifetime performance, which maintains 810 mAh g−1 after 200 cycles (100 mA g−1), 697 mAh g−1 after 520 cycles (200 mA g−1) and 500 mAh g−1 after 700 cycles (at 500 mA g−1). More importantly, this wet-chemistry/freeze-drying approach is general, and can be extended to other TMOs and MXenes to fabricate corresponding TMO QDs/MXene composites for various applications.

Flexible and free-standing 2D titanium carbide film decorated with manganese oxide nanoparticles as a high volumetric capacity electrode for supercapacitor

Abstract Developing flexible energy storage materials with high volumetric performances for portable electronic applications is arousing increasing interest in recent years. Herein, we presented a simple in-situ wet chemistry synthetic method to prepare flexible and free-standing MnO x -Ti 3 C 2 hybrid films, consisting of few-layered titanium carbide nanosheets and manganese oxide nanoparticles, which exhibited promising electrochemical performances as electrodes of supercapacitors. Hybridized nanoparticles of Mn 2 O 3 and MnO are anchored on the surface of delaminated Ti 3 C 2 nanolayers through electrostatic interactions. Such unique film based electrodes have a volumetric capacitance of 602.0 F cm −3 at 2 mV s −1 . Also, symmetric supercapacitors based on the MnO x -Ti 3 C 2 electrodes show an excellent energy stored capacity (13.64 mWh cm −3 ) and a very high long-term cycle stability with 89.8% capacitance retention after 10000 circles. Hence, these highly flexible and free-standing MnO x -Ti 3 C 2 films could be potential candidates as electrodes for flexible supercapacitors.

Organic‐Base‐Driven Intercalation and Delamination for the Production of Functionalized Titanium Carbide Nanosheets with Superior Photothermal Therapeutic Performance

AbstractThe delamination of titanium carbide sheets, an intriguing class of two‐dimensional materials, has been critically dependent on the extraction of interlayer Al in acidic media, such as concentrated hydrofluoric acid (HF) or a mixture of hydrochloric acid (HCl) and a fluoride salt. Herein, we report an organic‐base‐driven intercalation and delamination of titanium carbide that takes advantage of the amphoteric nature of interlayer Al. The resulting aluminum‐oxoanion‐functionalized titanium carbide sheets manifested unusually strong optical absorption in the near‐infrared (NIR) region with a mass extinction coefficient as high as 29.1 L g−1 cm−1 at 808 nm. Thus, the performance of this material is comparable or even superior to that of state‐of‐the‐art photoabsorption materials, including gold‐based nanostructures, carbon‐based materials, and transition‐metal dichalcogenides. Preliminary studies show that the titanium carbide sheets serve as efficient photothermal agents against tumor cells.

Organic-Base-Driven Intercalation and Delamination for the Production of Functionalized Titanium Carbide Nanosheets with Superior Photothermal Therapeutic Performance.

The delamination of titanium carbide sheets, an intriguing class of two-dimensional materials, has been critically dependent on the extraction of interlayer Al in acidic media, such as concentrated hydrofluoric acid (HF) or a mixture of hydrochloric acid (HCl) and a fluoride salt. Herein, we report an organic-base-driven intercalation and delamination of titanium carbide that takes advantage of the amphoteric nature of interlayer Al. The resulting aluminum-oxoanion-functionalized titanium carbide sheets manifested unusually strong optical absorption in the near-infrared (NIR) region with a mass extinction coefficient as high as 29.1 L g-1 cm-1 at 808 nm. Thus, the performance of this material is comparable or even superior to that of state-of-the-art photoabsorption materials, including gold-based nanostructures, carbon-based materials, and transition-metal dichalcogenides. Preliminary studies show that the titanium carbide sheets serve as efficient photothermal agents against tumor cells.