Roadmap and Direction toward High-Performance MoS₂ Hydrogen Evolution Catalysts

Abstract

MoS2 is a typical 2D transition metal dichalcogenide, and have exhibit superior electrocatalytic HER activity. The MoS2's HER catalysis was developed 15 years ago, various nanofabrication strategies are applied to boost the performance. It is promising that MoS2 would take place of Pt in HER catalysis. Various active catalytic sites, including edge, vacant, basal plane, etc. are developed and the catalytic performance were compared. Hybrid composition were developed, like modification with atoms, clusters, loading on substrates were developed. We make a summary on HER mechanisms varies with active sites and operation solutions. MoS2 synthesis, characterization, HER performance, mechanisms, to make a holistic understanding on the interplay between the structure, chemistry, HER performance, and mechanism. It is believed that the review will help researchers to get a better understanding on MoS2's superior HER performance, and provide a wealth of catalyst tool box to promote next-generation catalysts development. Main textHydrogen energy is perceived as the most promising clean energy without any carbon emission like CO2. For the greenhouse effect is becoming increasingly serious issue caused by large application of fossil fuel, hydrogen fuel is an innovative solution and show great potential in resolute carbon emission. Electrocatalytic water splitting is the best achievable approach nowadays for achieving large amount of H2. MoS2 are facile, stable, non-toxic, affordable materials with reasonable price, and have exhibit its superior potential in catalysis, sensing, opt electrochemical, environmental relate application 1 , etc. Modification of MoS2 materials has been widely applied for adjusting and formulate the relative performance in certain application field. MoS2 is a typical transition metal dichalcogenide 2 (TMD) compound with a two-dimensional S-Mo-S tri-atom layer structure. MoS2 is predicted to be a promising substitute catalyst for platinum 15 years ago 3 . While pristine MoS2 shows low electrocatalysis performance, via vacancies engineering, phase engineering, heterojunction engineering, hetero-atom doping strategies, the catalytic active sites quantities are elevated and catalysis performance is magnitude improved. We summarize on MoS2 synthesis, characterization, HER performance, mechanisms, to make a holistic understanding on the interplay between the structure, chemistry, HER performance, and mechanism, which will give directions to elevate other electrochemical reaction by MoS2. Structural, fundamental physical and chemical properties of MoS2:MoS2 has been applied as lubricant materials at industrial level in alleviate worn out phenomenon [4][5] . Generally, two-dimensional MoS2 exist 4 main crystal structure, which are 1H, 1T, 2H, 3R 6 . Figure 3. Phase transition between 1T and 2H mechanism based on the crystal field theory 11 . Schematic models of single-layered MoS2 with 2H (a) (Adapted with permission from ref. 10.

A concise discussion on MoS2basal plane activation toward the ennoblement of electrocatalytic HER output

“…Lei et al 55 in his review on 2D-MoS 2 provided information regarding different aspects of MoS 2 including several synthetic methods for its basal plane activation along with a wide range of application in various fields. Similarly, Meng et al 56 and Yang Cao 57 also published a review regarding basal plane activation of MoS 2 toward HER. With this concern, herein, we aim to present our current review encapsulating the advances achieved till date regarding the activation of chemically inert basal planes of MoS 2 and focusing on its application as an HER catalyst in a different and convenient way.…”

Recent advances in MoS2-based materials for electrocatalysis

“…Both theoretical 44 and experimental 81 results have identified the edges of MoS 2 as its catalytically active sites, but its basal plane is rather inert for the HER, which renders MoS 2 with limited catalytic activities. 12,40,82 In this regard, enormous progress has been made in the past decades for achieving higher catalytic performances of MoS 2 -based materials towards the HER. Therefore, in the following section, we will discuss some useful strategies for improving MoS 2 -based materials towards HER activity, which include doping, heterojunctions, MoS 2 nanomaterials with conductive supporting materials, defect-MoS 2 electrocatalysts, and turning the phase of MoS 2 from 2H to 1T.…”

“…85,86 It provides other advantages such as improved electronic carrier density, enhanced water adsorption, and phase transition, greatly enhancing the overall conductivity and reaction kinetics. 40…”

“…Moreover, both the core and shell of a heterostructure make contributions to improving the overall catalytic performances. 40,107,108 Wu et al 107 synthesized the hierarchical MoS 2 @MoP core–shell catalyst for the HER with low overpotential values of 42 mV and 29 mV in 1 M KOH and 0.5 M H 2 SO 4 , respectively. MoS 2 and MoP simultaneously make contributions to elevate the HER performance.…”

“…Recently, due to the unique electrochemical catalytic performance and easy availability, 2D transition metal dichalcogenides (TMDs) have attracted the interest of researchers. 39–42 This type of material has a general formula MX 2 , where M can represent Mo, W, Ti, Zr, and V, etc. , and X can represent S, Se, and Te.…”