Gold Nanoclusters Grown on MoS2 Nanosheets by Pulsed Laser Deposition: An Enhanced Hydrogen Evolution Reaction

Role of Transition Metal Dichalcogenides as a Catalyst Support for Decorating Gold Nanoparticles for Enhanced Hydrogen Evolution Reaction

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.

Structural Significance of Hydrophobic and Hydrogen Bonding Interaction for Nanoscale Hybridization of Antiseptic Miramistin Molecules with Molybdenum Disulfide Monolayers

This paper reports an easy route to immobilize the antiseptic drug miramistin (MR) molecules between the sheets of molybdenum disulfide, known for excellent photothermal properties. Two hybrid layered compounds (LCs) with regularly alternating monolayers of MR and MoS₂, differing in thickness of organic layer are prepared and studied by powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), density functional theory (DFT) calculations and quantum theory of atoms in molecules (QTAIM) topological analysis. The obtained structural models elucidate the noncovalent interaction network of MR molecules confined in the two-dimensional spacing surrounded by sulfide sheets. It emerged that the characteristic folded geometry of MR molecule previously evidenced for pure miramistin is preserved in the hybrid structures. Quantification of the energetics of bonding interactions unveils that the most important contribution to structure stabilization of both compounds is provided by the weak but numerous CH…S bonding contacts. They are accompanied by the intra- and inter-molecular interactions within the MR layers, with dominating bonding effect of intermolecular hydrophobic interaction. The results obtained in the models provide a comprehensive understanding of the driving forces controlling the assembly of MR and MoS₂ and may lead towards the development of novel promising MoS₂-based photothermal therapeutic agents.

Electrodeposition of Molybdenum Disulfide (MoS2) Nanoparticles on Monocrystalline Silicon

Molybdenum disulfide (MoS2) has attracted great attention for its unique chemical and physical properties. The applications of this transition metal dichalcogenide (TMDC) range from supercapacitors to dye-sensitized solar cells, Li-ion batteries and catalysis. This work opens new routes toward the use of electrodeposition as an easy, scalable and cost-effective technique to perform the coupling of Si with molybdenum disulfide. MoS2 deposits were obtained on n-Si (100) electrodes by electrochemical deposition protocols working at room temperature and pressure, as opposed to the traditional vacuum-based techniques. The samples were characterized by X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Rutherford Back Scattering (RBS).