Liquid Phase Exfoliation of 2D Materials and Its ElectrochemicalApplications in the Data-Driven Future

The electrochemical properties of 2D materials,particularly transition metal dichalcogenides(TMDs),hinge ontheir structural and chemical characteristics.To be practicallyviable,achieving large-scale,high-yield production is crucial,ensuring both quality and electrochemical suitability forapplications in energy storage,electrocatalysis,and potentialbasedionic sieving membranes.A prerequisite for success is a deepunderstanding of the synthesis process,forming a critical linkbetween materials synthesis and electrochemical performance.Thisreview extensively examines the liquid-phase exfoliation technique,providing insights into potential advancements and strategies tooptimize the TMDs nanosheet yield while preserving theirelectrochemical attributes.The primary goal is to compiletechniques for enhancing TMDs nanosheet yield through direct liquid-phase exfoliation,considering parameters like solvents,surfactants,centrifugation,and sonication dynamics.Beyond addressing the exfoliation yield,the review emphasizes the potentialimpact of these parameters on the structural and chemical properties of TMD nanosheets,highlighting their pivotal role inelectrochemical applications.Acknowledging evolving research methodologies,the review explores integrating machine learning anddata science as tools for understanding relationships and key characteristics.Envisioned to advance 2D material research,includingthe optimization of graphene,MXenes,and TMDs synthesis for electrochemical applications,this compilation charts a coursetoward data-driven techniques.By bridging experimental and machine learning approaches,it promises to reshape the landscape ofknowledge in electrochemistry,offering a transformative resource for the academic community.

Thermo-responsive graphene dispersions by liquid phase exfoliation of graphite aided by an alkylated Percec monodendron

Large-scale production of graphene and sub- sequent sample engineering is the key for fully-realizing the potential applications proposed to this intriguing two-dimensional nanomaterial. Herein, smart graphene dispersions with low defects and thermo-responsive properties can be obtained by liquid phase exfoliation of graphite using an alkylated Percec monodendron （3,4,5-trioctadecy- loxybenzaldehyde, 1） as the stabilizing reagent. By simply changing the temperature, the dispersed graphene and 1 can be detached, leading to the recovery of both components. Besides noncovalent wrapping, the stabilizing reagent 1 can be also covalently attached to graphene through [3＋2] cycloaddition. The covalently functionalized graphene sheets show improved dispersibility in organic solvents compared to the pristine graphene, which opens the door for their applications in various polymer matrixes. The strategy demonstrated here provides a new methodology to get smart graphene dispersions with multiple functions.

Extensive study of optical contrast between bulk and nanoscale transition metal dichalcogenide semiconductors

A remarkable refinement in the optical behavior of two-dimensional transition metal dichalcogenides(TMDs)has been brought to light when cleaved from their respective bulks.These atomically thin direct bandgap semiconductors are highly responsive to optical energy which proposes the route for futuristic photonic devices.In this manuscript,we have substantially focused on the optical study of MoS_(2)and WS_(2)nanosheets and comparative analysis with their bulk counterparts.The synthesis of nanosheets has been accomplished with liquid exfoliation followed by fabrication of thin films with drop-casting technique.X-ray diffraction and field emission scanning electron microscopy affirmed the morphology,whereas,UV-visible spectroscopy served as the primary tool for optical analysis.It was observed that several parameters,like optical conductivity,optical band-gap energy etc.have enhanced statistics in the case of exfoliated nanosheets as compared to their respective bulks.Some researchers have touched upon this analysis for MoS_(2),but it is completely novel for WS_(2).We expect our work to clearly distinguish between the optical behaviors of nanoscale and bulk TMDs so as to intensify and strengthen the research related to 2D-layered materials for optoelectronic and photovoltaic applications.

Review of the role of ionic liquids in two-dimensional materials

Ionic liquids(ILs)are expected to be used as readily available“designer”solvents,characterized by a number of tunable properties that can be obtained by modulating anion and cation combinations and ion chain lengths.Among them,its high ionicity is outstanding in the preparation and property modulation of two-dimensional(2D)materials.In this review,we mainly focus on the ILs-assisted exfoliation of 2D materials towards large-scale as well as functionalization.Meanwhile,electric-field controlled ILs-gating of 2D material systems have shown novel electronic,magnetic,optical and superconducting properties,attracting a broad range of scientific research activities.Moreover,ILs have also been extensively applied in various field practically.We summarize the recent developments of ILs modified 2D material systems from the electrochemical,solar cells and photocatalysis aspects,discuss their advantages and possibilities as“designer solvent”.It is believed that the design of ILs accompanying with diverse 2D materials will not only solve several scientific problems but also enrich materials design and engineer of 2D materials.

Tunable nitrogen crafted 2D-graphene nano-hybrid from industrial expansive and ecological approach as robust cathode microporous layer to improve performance of a direct methanol fuel cell

In this work, the excess water-stagnation issue in the high current region in direct methanol fuel cells(DMFCs) is resolved by using atomic precision modulated nitrogen-crafted graphene(NG) in the cathode microporous layer by utilizing simplistic,industrial-expansive and ecological strategy. Few-layer 2D-graphene(~2–5 nm thickness) is prepared by bath sonication approach from abundant feedstock-graphite and is treated with nitric acid to yield 1.8 wt.% uniformly dispersed nitrogen containing NG. Specifically, 1:4 weight ratio NG:carbon-black(CB) hybrid architecture, displays 0.252 V in 370 mA cm^(-2) with the peak power density of 93.4 mW cm^(-2), improving cell power density by 45.6% compared with standard one at 60℃ and 1 mol/L methanol/oxygen conditions at ultra-low catalyst loadings and displaying exceptional stability. Atomic insights into NG reveal that interplay between bonding configurations, altered hydrophobic/hydrophilic porosity of graphene(10.6% less wettability from contact angle and 13.1% high electrode porosity measurements) contribute to the better mass-transport-porogenic effect(16.3% high oxygen-permeability), mildly affecting the electron pathway(6.5% reduced in-plane electrical conductivity),overall significantly improving cell performance. Altogether, this work delivers multiple advantages, i.e., the usage of material from facile, sustainable and cost-effective routes, while improving DMFC performance with potential industrial promise.

Solution processed MoS2-PVA composite for subbandgap mode-locking of a wideband tunable ultrafast Er：fiber laser

We fabricate a free-standing few-layer molybdenum disulfide （MoS2）-polymer composite by liquid phase exfoliation of chemically pristine MoS2 crystals and use this to demonstrate a wideband tunable, ultrafast mode-locked fiber laser. Stable, picosecond pulses, tunable from 1,535 nm to 1,565 nm, are generated, corresponding to photon energies below the MoS2 material bandgap. These results contribute to the growing body of work studying the nonlinear optical properties of transition metal dichalcogenides that present new opportunities for ultrafast photonic applications.