Author Correction: High permeability sub-nanometre sieve composite MoS2 membranes

An amendment to this paper has been published and can be accessed via a link at the top of the paper

High permeability sub-nanometre sieve composite MoS2 membranes

Two-dimensional membranes have gained enormous interest due to their potential to deliver precision filtration of species with performance that can challenge current desalination membrane platforms. Molybdenum disulfide (MoS2) laminar membranes have recently demonstrated superior stability in aqueous environment to their extensively-studied analogs graphene-based membranes; however, challenges such as low ion rejection for high salinity water, low water flux, and low stability over time delay their potential adoption as a viable technology. Here, we report composite laminate multilayer MoS2 membranes with stacked heterodimensional one- to two-layer-thick porous nanosheets and nanodisks. These membranes have a multimodal porous network structure with tunable surface charge, pore size, and interlayer spacing. In forward osmosis, our membranes reject more than 99% of salts at high salinities and, in reverse osmosis, small-molecule organic dyes and salts are efficiently filtered. Finally, our membranes stably operate for over a month, implying their potential for use in commercial water purification applications

Two-Dimensional Vanadium Carbide (MXene) as a High-Capacity Cathode Material for Rechargeable Aluminum Batteries

Rechargeable aluminum batteries (Al batteries) can potentially be safer, cheaper, and deliver higher energy densities than those of commercial Li-ion batteries (LIBs). However, due to the very high charge density of Al³⁺ cations and their strong interactions with the host lattice, very few cathode materials are known to be able to reversibly intercalate these ions. Herein, a rechargeable Al battery based on a two-dimensional (2D) vanadium carbide (V₂CT_<i>x</i>) MXene cathode is reported. The reversible intercalation of Al³⁺ cations between the MXene layers is suggested to be the mechanism for charge storage. It was found that the electrochemical performance could be significantly improved by converting multilayered V₂CT_<i>x</i> particles to few-layer sheets. With specific capacities of more than 300 mAh g^–1 at high discharge rates and relatively high discharge potentials, V₂CT_<i>x</i> MXene electrodes show one of the best performances among the reported cathode materials for Al batteries. This study can lead to foundations for the development of high-capacity and high energy density rechargeable Al batteries by showcasing the potential of a large family of intercalation-type cathode materials based on MXenes

Two-Dimensional Vanadium Carbide (MXene) as a High-Capacity Cathode Material for Rechargeable Aluminum Batteries

Rechargeable aluminum batteries (Al batteries) can potentially be safer, cheaper, and deliver higher energy densities than those of commercial Li-ion batteries (LIBs). However, due to the very high charge density of Al³⁺ cations and their strong interactions with the host lattice, very few cathode materials are known to be able to reversibly intercalate these ions. Herein, a rechargeable Al battery based on a two-dimensional (2D) vanadium carbide (V₂CT_<i>x</i>) MXene cathode is reported. The reversible intercalation of Al³⁺ cations between the MXene layers is suggested to be the mechanism for charge storage. It was found that the electrochemical performance could be significantly improved by converting multilayered V₂CT_<i>x</i> particles to few-layer sheets. With specific capacities of more than 300 mAh g^–1 at high discharge rates and relatively high discharge potentials, V₂CT_<i>x</i> MXene electrodes show one of the best performances among the reported cathode materials for Al batteries. This study can lead to foundations for the development of high-capacity and high energy density rechargeable Al batteries by showcasing the potential of a large family of intercalation-type cathode materials based on MXenes

Shear delamination of multilayer MXenes

MXenes, a class of two-dimensional (2D) materials, are synthesized by etching MAX phase precursors to produce multilayer MXenes, where individual 2D sheets are held together by van der Waals forces. Typically, single 2D flakes of MXene are produced by chemical intercalation to delaminate multilayer MXenes, which is a time-intensive process that produces excess waste. In addition, intercalants affect the properties of MXenes. Many of them are toxic, limiting medical applications. Moreover, the process does not work for certain MXene chemistries, such as halogen-terminated MXenes produced by molten salt etching. This work demonstrates an alternative approach, shearing multilayer MXenes with a three-roll mill to produce single- and few-layer Ti3C2Tx flakes without chemical intercalants. The high shear produced Ti3C2Tx flakes showed a capacitance of 337 F g(-1), comparable to flakes made with LiCl intercalation, in 3 M H2SO4. We generalize this approach by shear delamination of other MXenes.Web of Scienc

Room Temperature Gas Sensing of Two-Dimensional Titanium Carbide (MXene)

Wearable gas sensors have received lots of attention for diagnostic and monitoring applications, and two-dimensional (2D) materials can provide a promising platform for fabricating gas sensors that can operate at room temperature. In the present study, the room temperature gas-sensing performance of Ti₃C₂T_<i>x</i> nanosheets was investigated. 2D Ti₃C₂T_<i>x</i> (MXene) sheets were synthesized by removal of Al atoms from Ti₃AlC₂ (MAX phases) and were integrated on flexible polyimide platforms with a simple solution casting method. The Ti₃C₂T_<i>x</i> sensors successfully measured ethanol, methanol, acetone, and ammonia gas at room temperature and showed a p-type sensing behavior. The fabricated sensors showed their highest and lowest response toward ammonia and acetone gas, respectively. The limit of detection of acetone gas was theoretically calculated to be about 9.27 ppm, presenting better performance compared to other 2D material-based sensors. The sensing mechanism was proposed in terms of the interactions between the majority charge carriers of Ti₃C₂T_<i>x</i> and gas species

Pristine Ti3C2Tx MXene Enables Flexible and Transparent Electrochemical Sensors

In the era of the internet of things, there exists a pressing need for technologies that meet the stringent demands of wearable, self-powered, and seamlessly integrated devices. Current approaches to developing MXene-based electrochemical sensors involve either rigid or opaque components, limiting their use in niche applications. This study investigates the potential of pristine Ti3C2Tx electrodes for flexible and transparent electrochemical sensing, achieved through an exploration of how material characteristics (flake size, flake orientation, film geometry, and uniformity) impact the electrochemical activity of the outer sphere redox probe ruthenium hexamine using cyclic voltammetry. The optimized electrode made of stacked large Ti3C2Tx flakes demonstrated excellent reproducibility and resistance to bending conditions, suggesting their use for reliable, robust, and flexible sensors. Reducing electrode thickness resulted in an amplified faradaic-to-capacitance signal, which is advantageous for this application. This led to the deposition of transparent thin Ti3C2Tx films, which maintained their best performance up to 73% transparency. These findings underscore its promise for high-performance, tailored sensors, marking a significant stride in advancing MXene utilization in next-generation electrochemical sensing technologies. The results encourage the analytical electrochemistry field to take advantage of the unique properties that pristine Ti3C2Tx electrodes can provide in sensing through more parametric studies

Pristine Ti₃C₂T_<i>x</i> MXene Enables Flexible and Transparent Electrochemical Sensors

In the era of the internet of things, there exists a pressing need for technologies that meet the stringent demands of wearable, self-powered, and seamlessly integrated devices. Current approaches to developing MXene-based electrochemical sensors involve either rigid or opaque components, limiting their use in niche applications. This study investigates the potential of pristine Ti3C2Tx electrodes for flexible and transparent electrochemical sensing, achieved through an exploration of how material characteristics (flake size, flake orientation, film geometry, and uniformity) impact the electrochemical activity of the outer sphere redox probe ruthenium hexamine using cyclic voltammetry. The optimized electrode made of stacked large Ti3C2Tx flakes demonstrated excellent reproducibility and resistance to bending conditions, suggesting their use for reliable, robust, and flexible sensors. Reducing electrode thickness resulted in an amplified faradaic-to-capacitance signal, which is advantageous for this application. This led to the deposition of transparent thin Ti3C2Tx films, which maintained their best performance up to 73% transparency. These findings underscore its promise for high-performance, tailored sensors, marking a significant stride in advancing MXene utilization in next-generation electrochemical sensing technologies. The results encourage the analytical electrochemistry field to take advantage of the unique properties that pristine Ti3C2Tx electrodes can provide in sensing through more parametric studies