2D Metallic Transitional Metal Dichalcogenides for Electrochemical Hydrogen Evolution

Abstract

2D metallic transition metal dichalcogenides (MTMDCs) have become the focus of intense research in many fields due to their novel physical and chemical properties (e.g., charge‐density wave order, unconventional superconductivity, and magnetism), as well as their extraordinary performance in advanced nanoelectronics and energy‐related fields. Herein, the preparation methods of 2D MTMDCs, such as chemical exfoliation via alkali metal intercalation, colloidal synthesis, and chemical vapor deposition (CVD), and their applications in electrocatalytic hydrogen evolution reactions (HERs) are comprehensively discussed. In particular, the first part focuses on various synthetic routes of 2D MTMDC nanosheets with different thicknesses and domain sizes, as well as the crucial factors in the corresponding synthetic process. In addition, the different growth mechanisms via the CVD processes caused by common insulating substrates (e.g., SiO2/Si, mica), unique conducing substrates (e.g., Au foil), and novel porous substrates (e.g., nanoporous gold) are also compared. In the second part, the excellent electrocatalytic performances of 2D MTMDC nanosheets in HER are also demonstrated by combining density functional theory (DFT) calculations and experimental results. Finally, challenges regarding the preparation of MTMDC nanosheets and probable routes for further improving the HER performance are also highlighted, and the future research directions are also proposed.

Numerical experiments on the dynamics of two-dimension charge-density-waves (CDW’s) system in the presence of the weak interchain interaction effect

“…where k and d are respectively, a constant and an exponent, such that d < < 0 1. d depend on the force applied to represent the CDWs (external electric field), a fit of the figure 4 curves with equation (11), shows that this exponent increases as a function of the applied electric field (table 1).…”

“…These weak interactions enable to obtain a two-dimensional (2D) layers with few-nanometer thickness from the corresponding bulk CDW crystals [9]. Recently, there has been a new rebirth of interest in 2D CDW compounds around the world [10][11][12][13] because of their extraordinary properties that are found to be absent in conventional bulk CDW materials [14][15][16][17][18] and which has opened the way into examining their potential in a lot of applications such as radiation-hard electronics [19], communications [20], etc Furthermore, attempts to detect sliding effect in these systems knew success, despite the fail-over the past [21]. For instance, the nonlinear current-voltage characteristic was found for layered DyTe 3 compound [22].…”

Substitution of copper atoms into defect-rich molybdenum sulfides and their electrocatalytic activity

“…Two-dimensional transition metal dichalcogenides (2D TMDCs) have gained significant interest due to their versatile and unique electrical, optical, chemical, and mechanical properties, with practicable applications in electrocatalysts, photocatalysts, energy storage, and optoelectronics. 1,2,3,4 In general, TMDCs are layered materials represented by MX 2 , where a layer of transition metal atoms (M) is sandwiched between two layers of chalcogen atoms (X). Until now, 40 different types of layered TMDCs exist, with Sulphur, Selenium, and Tellurium forming layered compounds with nine metals from group IV, V, VI, VII, and IX (Ti, Zr, Hf, V, Nb, Ta, Mo, W, Tc, Re, Pd, and Pt) and with Co, Rh, Ir, and Ni partially.…”