2D Transition Metal Dichalcogenides: Design, Modulation, and Challenges in Electrocatalysis

Abstract

Hydrogen has been deemed as an ideal substitute fuel to fossil energy because of its renewability and the highest energy density among all chemical fuels. One of the most economical, ecofriendly, and high‐performance ways of hydrogen production is electrochemical water splitting. Recently, 2D transition metal dichalcogenides (also known as 2D TMDs) showed their utilization potentiality as cost‐effective hydrogen evolution reaction (HER) catalysts in water electrolysis. Herein, recent representative research efforts and systematic progress made in 2D TMDs are reviewed, and future opportunities and challenges are discussed. Furthermore, general methods of synthesizing 2D TMDs materials are introduced in detail and the advantages and disadvantages for some specific methods are provided. This explanation includes several important regulation strategies of creating more active sites, heteroatoms doping, phase engineering, construction of heterostructures, and synergistic modulation which are capable of optimizing the electrical conductivity, exposure to the catalytic active sites, and reaction energy barrier of the electrode material to boost the HER kinetics. In the last section, the current obstacles and future chances for the development of 2D TMDs electrocatalysts are proposed to provide insight into and valuable guidelines for fabricating effective HER electrocatalysts.

In Situ Wet Etching of MoS2@dWO3 Heterostructure as Ultra-Stable Highly Active Electrocatalyst for Hydrogen Evolution Reaction

“…All the positions of S 2p 1/2 , S 2p 3/2 peak were in accordance with the previous literature ( Figure 2d) [24]. However, we observed that the peak of S 2-2p3/2 have 0.05 eV shift toward low blinding energy, which indicated that S became easier to obtain electrons after forming heterostructure [45] and also confirmed peak of Mo 6+ 3d5/2 (232.63 eV) and Mo 6+ 3d3/2 (235.73 eV) were further enhanced because of the conservation of gain and loss electrons [5]. In summary, formation of heterostructure caused the increase of O-vacancies on the defective WO 3 surface and the generation of Mo-O bond by oxygen incorporation into MoS 2 layer.…”

“…Electrocatalysts water-splitting product hydrogen is reproducible and clean energy [1][2][3]. The development of platinum (Pt)-free electrocatalysts is a crucial problem to improve the generally efficiency for hydrogen evolution reaction (HER), especially when facing resources shortage and energy crisis [4][5][6]. Newly, two-dimensional (2D) transition metal chalcogenides have always been mentioned, such as molybdenum disulfide (MoS 2 ) [7,8], tungsten oxide (WO 3 ) [9,10], molybdenum selenide (MoSe 2 ) [11,12] and can demonstrated to clarify the mechanism for HER in strong acids.…”

“…Though many literatures have been reported the great potential of MoS 2 as HER electrocatalyst [3,21,22], the severe stacking of MoS 2 nanosheets during the preparation and electrochemical reaction process significantly impact its stability and hinders its application compared with Pt-based electrocatalysts [21,23]. Therefore, unless the electronic structure can be appropriately modulated by varying the chemical constituents [18] to increase the population of active sites [17] or introducing durable supportive materials [5,24] to prevent the aggregation, the 2D layered MoS 2 could hardly be employed into practical application without long-term stability [25].…”

Controlled Growth of Edge‐Enriched ReS2 Nanoflowers on Carbon Cloth Using Chemical Vapor Deposition for Hydrogen Evolution

“…Second, electrical conductivity is another essential requirement for an advanced electrocatalyst. [6,7,12,31] However, the intrinsic low conductivity of ReS 2 impedes its application in HER. [31,32] Synergizing or coupling with conductive substrates is a common method to considerably enhance the conductivity of TMDCs.…”

“…The electrochemical water‐splitting through hydrogen evolution reaction (HER) has been considered as a sustainable way for producing hydrogen, a clean and renewable energy source. [ 1–7 ] Platinum (Pt) has been widely recognized as the best HER catalyst, but subject to its high cost and limited storage. Therefore, to replace Pt, many efforts have been devoted to electrocatalysts based on non‐noble metals such as transition metal complexes, oxides, phosphide, carbides, and transition metal dichalcogenides (TMDCs).…”