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2D materials are of interest in various applications such as energy conversion, storage, and sensing. These materials are prepared by bottom‐up or top‐down methods that are difficult to control and suffer from low yield. Synthesis in molten salt is suggested as an alternative in which the balance between exfoliation and solubility is explored. It is demonstrated that when a pellet of 2D material is insoluble in molten salt (graphite in any salt), it is exfoliated. For low solubility (MoS2 in NaCl/KCl), the 2D material nucleates and grows into a small flowerlike structure composed of thin MoS2 sheets through Ostwald ripening. For high solubility in the molten salt (MoS2 in CsCl), it forms larger flowers. Herein, the molten salt treatment of high and low surface area MoS2 (micron‐size particles and a single large pellet, respectively) is compared. The particles yielded facet MoS2 crystals through dissolution–nucleation–recrystallization process and the pellet yielded flowers. Herein, methods for synthesizing 2D materials with controllable size and shape are promoted by simple molten salt treatment that opens an avenue to the development of soluble (MoS2) and non‐soluble (graphite) materials with different morphologies in a simple and affordable way. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising renewable energy source. However, its implementation in industrial processes is challenging since it penetrates metals, resulting in embrittlement, leakage, and a risk of explosion. We explore the combined effect of loading a polymer liner (protecting the metal) with graphene and unsaturated organic molecules on reducing hydrogen diffusion. The suggested combined approach includes (1) the formation of a hydrogen barrier and (2) the chemical absorption of hydrogen. In (1), graphene nanoplatelets (GNPs, impermeable to hydrogen) decrease hydrogen diffusion by one order of magnitude, where small-sized GNPs are found to be more effective than large ones. In (2), the presence of unsaturated organic molecules (getter) not only leads to an efficient chemical absorption of hydrogen (>86% reaction) but decreases its diffusion by two orders of magnitude. The kinetic analysis of a hybrid system (loaded with both the GNP and getter) reveals that the presence of GNPs allows hydrogen to reach distant locations of unsaturated molecules by migrating over the GNP surface (termed spillover). A polymer loaded with unsaturated organic molecules changes its color upon exposure to hydrogen and could serve as a standalone visual hydrogen sensor. These findings provide general guiding principles for designing functional materials for hydrogen detection and its safe transportation and storage. [ABSTRACT FROM AUTHOR]

Dispersion and exfoliation of carbon nanotubes (CNT) by water soluble dispersants such as surfactant, polymer or protein is a key step toward the application of carbon nanotubes in composite materials, biochemical and biomedical applications. Upon dispersion, the solution phase separates into dispersed nanotubes in the supernatant and a precipitate phase including carbonaceous impurities but also nanotubes and dispersants. Yet, simple but accurate tools for measuring the concentrations of the constituents are not available. In most studies a comparison between CNT suspensions is based on ocular observation or on UV-visible measurement of a featureless spectrum at single wavelength. Such measurements are complex since both nanotubes and most dispersants absorb along the whole UV-visible spectrum and an overlap of their signals occurs. In this paper we employ chemometric techniques to evaluate the pH effect on the concentration of both dispersant (protein-bovine serum albumin, BSA) and single-wall nanotube (SWNT) from a full UV-visible spectrum of aqueous solutions. We find strong correlation between the conformation of the protein and its dispersion efficiency.