Scaling the production of synthetic 2D materials to industrial quantities has faced significant challenges due to synthesis bottlenecks whereby few have been produced in large volumes. These challenges typically stem from bottom‐up approaches limiting the production to the substrate size or precursor availability for chemical synthesis and/or exfoliation. In contrast, MXenes, a large class of 2D transition metal carbides and/or nitrides, are produced via a top‐down synthesis approach. The selective wet etching process does not have similar synthesis constraints as some other 2D materials. The reaction occurs in the whole volume; therefore, the process can be readily scaled with reactor volume. Herein, the synthesis of 2D titanium carbide MXene (Ti3C2T
To advance the MXene field, it is crucial to optimize each step of the synthesis process and create a detailed, systematic guide for synthesizing high‐quality MXene that can be consistently reproduced. In this study, a detailed guide is provided for an optimized synthesis of titanium carbide (Ti3C2T
- NSF-PAR ID:
- 10419157
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small Methods
- Volume:
- 7
- Issue:
- 8
- ISSN:
- 2366-9608
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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x ) is studied in two batch sizes, 1 and 50 g, to determine if large‐volume synthesis affects the resultant structure or composition of MXene flakes. Characterization of the morphology and properties of the produced MXene using scanning electron microscopy, X‐ray diffraction, dynamic light scattering, Raman spectroscopy, X‐ray photoelectron spectroscopy, UV–visible spectroscopy, and conductivity measurements show that the materials produced in both batch sizes are essentially identical. This illustrates that MXenes experience no change in structure or properties when scaling synthesis, making them viable for further scale‐up and commercialization. -
Abstract Porous MXene-polymer composites have gained attention due to their low density, large surface area, and high electrical conductivity, which can be used in applications such as electromagnetic interference shielding, sensing, energy storage, and catalysis. High internal phase emulsions (HIPEs) can be used to template the synthesis of porous polymer structures, and when solid particles are used as the interfacial agent, composites with pores lined with the particles can be realized. Here, we report a simple and scalable method to prepare conductive porous MXene/polyacrylamide structures via polymerization of the continuous phase in oil/water HIPEs. The HIPEs are stabilized by salt flocculated Ti 3 C 2 T x nanosheets, without the use of a co-surfactant. After polymerization, the polyHIPE structure consists of porous polymer struts and pores lined with Ti 3 C 2 T x nanosheets, as confirmed by scanning electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The pore size can be tuned by varying the Ti 3 C 2 T x concentration, and the interconnected Ti 3 C 2 T x network allows for electrical percolation at low Ti 3 C 2 T x loading; further, the electrical conductivity is stable for months indicating that in these composites, the nanosheets are stable to oxidation at ambient conditions. The polyHIPEs also exhibit rapid radio frequency heating at low power (10 °C s −1 at 1 W). This work demonstrates a simple approach to accessing electrically conductive porous MXene/polymer composites with tunable pore morphology and good oxidation stability of the nanosheets.more » « less
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null (Ed.)Quaternary MAX phases, (Ta 1−x Ti x ) 3 AlC 2 ( x = 0.4, 0.62, 0.75, 0.91 or 0.95), have been synthesised via pressureless sintering of TaC, TiC, Ti and Al powders. Via chemical etching of the Al layers, (Ta 0.38 Ti 0.62 ) 3 C 2 T z – a new MXene, has also been synthesised. All materials contain an M-layer solid solution of Ta and Ti, with a variable Ta concentration, paving the way for the synthesis of a range of alloyed (Ta,Ti) 3 C 2 T z MXenes with tuneable compositions for a wide range of potential applications.more » « less
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Abstract 2D carbides and nitrides (MXenes) are widely recognized for their exceptional promise for numerous applications. However, physical property measurements of their individual monolayers remain very limited despite their importance for revealing the intrinsic physical properties of MXenes. The first mechanical and electrical measurements of individual single‐layer flakes of Nb4C3T
x MXene, which are prepared via an improved synthetic method are reported. Characterization of field‐effect transistor devices based on individual single‐layer Nb4C3Tx flakes shows an electrical conductivity of 1024 ± 165 S cm−1, which is two orders of magnitude higher than the previously reported values for bulk Nb4C3Tx assemblies, and an electron mobility of 0.41 ± 0.27 cm2V−1s−1. Atomic force microscopy nanoindentation measurements of monolayer Nb4C3Tx membranes yield an effective Young's modulus of 386 ± 13 GPa, assuming a membrane thickness of 1.26 nm. This is the highest value reported for nanoindentation measurements of solution‐processable 2D materials, revealing the potential of Nb4C3Tx as a primary component for various mechanical applications. Finally, the agreement between the mechanical properties of 2D Nb4C3Tx MXene and cubic NbC suggests that the extensive experimental data on bulk carbides could be useful for identifying new MXenes with improved functional characteristics. -
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Abstract MXenes constitute a rapidly growing family of 2D materials that are promising for optoelectronic applications because of numerous attractive properties, including high electrical conductivity. However, the most widely used titanium carbide (Ti3C2T
x ) MXene transparent conductive electrode exhibits insufficient environmental stability and work function (WF ), which impede practical applications Ti3C2Tx electrodes in solution‐processed optoelectronics. Herein, Ti3C2Tx MXene film with a compact structure and a perfluorosulfonic acid (PFSA) barrier layer is presented as a promising electrode for organic light‐emitting diodes (OLEDs). The electrode shows excellent environmental stability, highWF of 5.84 eV, and low sheet resistanceR Sof 97.4 Ω sq−1. The compact Ti3C2Tx structure after thermal annealing resists intercalation of moisture and environmental contaminants. In addition, the PFSA surface modification passivates interflake defects and modulates theWF . Thus, changes in theWF andR Sare negligible even after 22 days of exposure to ambient air. The Ti3C2Tx MXene is applied for large‐area, 10 × 10 passive matrix flexible OLEDs on substrates measuring 6 × 6 cm. This work provides a simple but efficient strategy to overcome both the limited environmental stability and lowWF of MXene electrodes for solution‐processable optoelectronics.
