Study of the molybdenum dichalcogenide crystals: recent developments and novelty of the P-MoS2 structure

Surface-Enhanced Raman Scattering Using 2D Materials

The use of surface-enhanced Raman scattering (SERS) as a technique for detecting small amounts of (bio)chemical analytes has become increasingly popular in various fields. While gold and silver nanostructures have been extensively studied as SERS substrates, the availability of other types of substrates is currently expanding the applications of this spectroscopic method. Recently, researchers have begun exploring two-dimensional (2D) materials (e. g., graphene-like nanostructures) as substrates for SERS analysis. These materials offer unique optical properties, a well-defined structure, and the ability to modify their surface chemistry. As a contribution to advance this field, this concept article highlights the significance of understanding the chemical mechanism that underlies the experimental Raman spectra of chemisorbed molecules onto 2D materials' surfaces. Therefore, the article discusses recent advancements in fabricating substrates using 2D layered materials and the synergic effects of using their metallic composites for SERS applications. Additionally, it provides a new perspective on using Raman imaging in developing 2D materials as analytical platforms for Raman spectroscopy, an exciting emerging research area with significant potential.

Recent Advances in Self-Powered Tactile Sensing for Wearable Electronics

With the arrival of the Internet of Things era, the demand for tactile sensors continues to grow. However, traditional sensors mostly require an external power supply to meet real-time monitoring, which brings many drawbacks such as short service life, environmental pollution, and difficulty in replacement, which greatly limits their practical applications. Therefore, the development of a passive self-power supply of tactile sensors has become a research hotspot in academia and the industry. In this review, the development of self-powered tactile sensors in the past several years is introduced and discussed. First, the sensing principle of self-powered tactile sensors is introduced. After that, the main performance parameters of the tactile sensors are briefly discussed. Finally, the potential application prospects of the tactile sensors are discussed in detail.

Capturing Carbon Dioxide by Co-Decorated Molybdenum Disulfide: Boosting Efficiency Achievement of a Porous Two-Dimensional Nanomaterial via DFT Study

Stable and efficient conversion of carbon dioxide (CO₂) into useful products provides a desirable path toward achieving green fuel. Accurate sensing of CO₂ capacity is also desired and can be reached as a result of conversion or adsorption. In this study, the electronic and structural properties of cobalt (Co) transition metal doped over the two-dimensional (2D) porous molybdenum disulfide (P-MoS₂) surface toward CO₂ adsorption were studied using the D3-corrected density functional theory (DFT-D3) method. Results confirm that there are three most stable sites for Co decoration over P-MoS₂, having led to a maximum number of CO₂ molecules each adsorbed on a Co atom. The Co atom intends to bind to the P-MoS₂ surface as a single, double, and double-sided catalyst. The Co binding capacity and CO₂ adsorption ability on the Co/P-MoS₂ including the most stable CO₂ possible structure were investigated. This work demonstrates maximizing CO₂ capture by providing the possibility of CO₂ adsorption on a double-sided Co-decorated P-MoS₂. Therefore, thin-layer two-dimensional catalyst has great potential for CO₂ capture and storage. The charge transfer in the process of CO₂ adsorption complexation on Co/P-MoS₂ is high and encourages the development of high-quality 2D materials for well-organized gas sensing applications.

MoS2 as a Co-Catalyst for Photocatalytic Hydrogen Production: A Mini Review

Molybdenum disulfide (MoS₂), with a two-dimensional (2D) structure, has attracted huge research interest due to its unique electrical, optical, and physicochemical properties. MoS₂ has been used as a co-catalyst for the synthesis of novel heterojunction composites with enhanced photocatalytic hydrogen production under solar light irradiation. In this review, we briefly highlight the atomic-scale structure of MoS₂ nanosheets. The top-down and bottom-up synthetic methods of MoS₂ nanosheets are described. Additionally, we discuss the formation of MoS₂ heterostructures with titanium dioxide (TiO₂), graphitic carbon nitride (g-C₃N₄), and other semiconductors and co-catalysts for enhanced photocatalytic hydrogen generation. This review addresses the challenges and future perspectives for enhancing solar hydrogen production performance in heterojunction materials using MoS₂ as a co-catalyst.

Wettability Scope of MoS2-Ionic Liquid Interfaces and Their Modification toward Novel Superhydrophobic Boundaries

In the past two decades, much interest has been given to properties and applications of 2D materials, mainly molybdenum disulfide (MoS₂). Understanding how liquids (particularly green liquids) interact with and wet the surfaces of the 2D materials has become essential to engineering synthesis methods and their applications. We used molecular dynamics (MD) simulation to model the wetting behavior and interfacial structure of imidazolium-based ([BMIM][BF₄] and [BMIM][NTf₂]) ionic liquid (IL) nanodroplets on various (1T-, 2H-, 3R-, and P-) MoS₂ crystal surfaces. The extent of the hydrophobicity, structure of the crystal surface, and anion types lead to a significantly different spreading mechanism and wetting behavior at room temperature. [BMIM][BF₄] IL spreads well on any MoS₂ surface, showing high and low spreading rates on 3R-MoS₂ and P-MoS₂, respectively. The slow spreading rate and wetting behavior on P-MoS₂ are influenced by the morphology and unique atom organization in terms of cavities and kinks. The equilibrated configuration for hydrophobic [BMIM][NTf₂] IL displayed an abnormal no-spreading structure on any MoS₂ surface. Conclusively, the newly developed P-MoS₂ structure found to possess a surface with stronger hydrophobicity than that of other crystal structures of MoS₂. We elucidate and present detailed aspects of surface modification of P-MoS₂ with a selected fluorooctylsilane coating to reach a superhydrophobic surface. In addition to assessing the fluorooctylsilane features by quantum chemical calculations in favor of film stability, the coating quality and suitability were vastly confirmed by the simulation of IL wetting behavior and the calculated contact angle (CA) of more than 150°. Therefore, the results of this work shed light on composite materials to generate a novel 2D superhydrophobic surface via a qualified fluorooctylsilane coating on the P-MoS₂ substrate.