Laminar membranes of two-dimensional materials are excellent candidates for applications in water filtration due to the formation of nanocapillaries between individual crystals that can exhibit a molecular and ionic sieving effect, while allowing high water flux. This approach has been exemplified previously with graphene oxide, however these membranes suffer from swelling when exposed to liquid water, leading to low salt rejection and reducing their applicability for desalination applications. Here, we demonstrate that by producing thin (∼5 μm) laminar membranes of exfoliated molybdenum disulfide (MoS₂) in a straightforward and scalable process, followed by a simple chemical functionalization step, we can efficiently reject ∼99% of the ions commonly found in seawater, while maintaining water fluxes significantly higher (∼5 times) than those reported for graphene oxide membranes. These functionalized MoS₂ membranes exhibit excellent long-term stability with no swelling and consequent decrease in ion rejection, when immersed in water for periods exceeding 6 months. Similar stability is observed when exposed to organic solvents, indicating that they are ideal for a variety of technologically important filtration applications.

The electrochemical properties of 2D materials, particularly transition metal dichalcogenides (TMDs), hinge on their structural and chemical characteristics. To be practically viable, achieving large-scale, high-yield production is crucial, ensuring both quality and electrochemical suitability for applications in energy storage, electrocatalysis, and potential-based ionic sieving membranes. A prerequisite for success is a deep understanding of the synthesis process, forming a critical link between materials synthesis and electrochemical performance. This review extensively examines the liquid-phase exfoliation technique, providing insights into potential advancements and strategies to optimize the TMDs nanosheet yield while preserving their electrochemical attributes. The primary goal is to compile techniques 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 potential impact of these parameters on the structural and chemical properties of TMD nanosheets, highlighting their pivotal role in electrochemical applications. Acknowledging evolving research methodologies, the review explores integrating machine learning and data science as tools for understanding relationships and key characteristics. Envisioned to advance 2D material research, including the optimization of graphene, MXenes, and TMDs synthesis for electrochemical applications, this compilation charts a course toward data-driven techniques. By bridging experimental and machine learning approaches, it promises to reshape the landscape of knowledge in electrochemistry, offering a transformative resource for the academic community.

The two-dimensional (2D) transition metal dichalcogenides (TMDs) have been widely used in various electrochemical applications, such as electrocatalysts, sensors, and energy storage. They have been potentially demonstrated not only as catalysts but also as supporting materials for boosting catalytic performance and durability. However, the different types of TMD nanosheets (transition metals and chalcogenide atoms) for supporting nanoparticles have not yet been investigated for electrocatalytic performance. Herein, we provide mechanistic insights into the hydrogen evolution reaction (HER) of various TMDs (i.e., MoS₂, MoSe₂, and WSe₂) as catalyst supports for the decoration of gold nanoparticles (AuNPs), which represent an active catalyst. Among various TMD supports, it was found that the MoS₂ supports with an optimal amount of AuNPs loading (MoS₂/AuNPs) exhibited excellent catalytic activity (low overpotential and Tafel slope), which is better than that of other TMD supports and the previously reported TMD-based support. This is due to well-dispersed AuNPs with the charge transfer of Au-MoS₂ interaction (increasing n-type), leading to highly active sites for HER performance. Moreover, the perfect laminar stacking of the MoS₂/AuNPs electrode, providing high porosity and good wettability, plays an important role in enhancing the ability of ionic electrolytes to infiltrate through the electrode area (up to ∼50 F g^-1). The MoS₂/AuNPs exhibit long-term stability with no disintegration of the electrode when performing the HER at ultrahigh current density (>200 mA cm^-2) for over 24 h. This work aims to deepen the understanding of TMD materials as catalyst supports, and is advantageous for the development of catalyst-based applications.