Recovery of oxidized two-dimensional MXenes through high frequency nanoscale electromechanical vibration.

MXenes hold immense potential given their superior electrical properties. The practical adoption of these promising materials is, however, severely constrained by their oxidative susceptibility, leading to significant performance deterioration and lifespan limitations. Attempts to preserve MXenes have been limited, and it has not been possible thus far to reverse the material's performance.

Improved charge storage performance of a layered MoC MXene/MoS/graphene nanocomposite.

The construction of nanocomposite electrodes based on 2D materials is an efficient route for property enrichment and for exploitation of constituent 2D materials. Herein, a flexible MoC -MXene/MoS/graphene (MOMG) composite electrode is constructed, utilizing an environment-friendly method for high-quality graphene and MoS synthesis. The presence of graphene and MoS between MXene sheets limits the commonly observed restacking, increases the interlayer spacing, and facilitates the ionic and electronic conduction.

Acoustomicrofluidic Synthesis of Pristine Ultrathin TiCT MXene Nanosheets and Quantum Dots.

The conversion of layered transition metal carbides and/or nitrides (MXenes) into zero-dimensional structures with thicknesses and lateral dimensions of a few nanometers allows these recently discovered materials with exceptional electronic properties to exploit the additional benefits of quantum confinement, edge effects, and large surface area. Conventional methods for the conversion of MXene nanosheets and quantum dots, however, involve extreme conditions such as high temperatures and/or harsh chemicals that, among other disadvantages, lead to significant degradation of the material as a consequence of their oxidation. Herein, we show that the large surface acceleration-on the order of 10 million 's-produced by high-frequency (10 MHz) nanometer-order electromechanical vibrations on a chip-scale piezoelectric substrate is capable of efficiently nebulizing, and consequently dimensionally reducing, a suspension of multilayer TiCT (MXene) into predominantly monolayer nanosheets and quantum dots while, importantly, preserving the material from any appreciable oxidation.

Ultrafast, One-Step, Salt-Solution-Based Acoustic Synthesis of TiC MXene.

The current quest for two-dimensional transition metal carbides and nitrides (MXenes) has been to circumvent the slow, hazardous, and laborious multistep synthesis procedures associated with conventional chemical MAX phase exfoliation. Here, we demonstrate a one-step synthesis method with local TiAlC MAX to TiCT MXene conversion on the order of milliseconds, facilitated by proton production through solution dissociation under megahertz frequency acoustic excitation. These protons combined with fluorine ions from LiF to selectively etch the MAX phase into MXene, whose delamination is aided by the acoustic forcing.

Flexible Free-Standing MoO/TiCT MXene Composite Films with High Gravimetric and Volumetric Capacities.

Enhancing both the energy storage and power capabilities of electrochemical capacitors remains a challenge. Herein, TiCT MXene is mixed with MoO nanobelts in various mass ratios and the mixture is used to vacuum filter binder free, open, flexible, and free-standing films. The conductive TiCT flakes bridge the nanobelts, facilitating electron transfer; the randomly oriented, and interconnected, MoO nanobelts, in turn, prevent the restacking of the TiCT nanosheets.

Ultrafast assembly of swordlike Cu(1,3,5-benzenetricarboxylate) metal-organic framework crystals with exposed active metal sites.

Owing to their large surface area and high uptake capacity, metal-organic frameworks (MOFs) have attracted considerable attention as potential materials for gas storage, energy conversion, and electrocatalysis. Various strategies have recently been proposed to manipulate the MOF surface chemistry to facilitate exposure of the embedded metal centers at the crystal surface to allow more effective binding of target molecules to these active sites. Nevertheless, such strategies remain complex, often requiring strict control over the synthesis conditions to avoid blocking pore access, reduction in crystal quality, or even collapse of the entire crystal structure.

Flexible Freestanding MoO -Carbon Nanotubes-Nanocellulose Paper Electrodes for Charge-Storage Applications.

Herein, a one-step synthesis protocol was developed for synthesizing freestanding/flexible paper electrodes composed of nanostructured molybdenum oxide (MoO ) embedded in a carbon nanotube (CNT) and Cladophora cellulose (CC) matrix. The preparation method involved sonication of the precursors, nanostructured MoO , CNTs, and CC with weight ratios of 7:2:1, in a water/ethanol mixture, followed by vacuum filtration. The electrodes were straightforward to handle and possessed a thickness of approximately 12 μm and a mass loading of MoO -CNTs of approximately 0.

Tailoring Structure, Composition, and Energy Storage Properties of MXenes from Selective Etching of In-Plane, Chemically Ordered MAX Phases.

The exploration of 2D solids is one of our time's generators of materials discoveries. A recent addition to the 2D world is MXenes that possses a rich chemistry due to the large parent family of MAX phases. Recently, a new type of atomic laminated phases (coined i-MAX) is reported, in which two different transition metal atoms are ordered in the basal planes.