Layered transition metal dichalcogenide electrochemistry: journey across the periodic table.

Studies on layered transition metal dichalcogenides (TMDs), in particular for Group VIB TMDs like MoS2 and WS2, have long reached a crescendo in the realms of electrochemical applications initiated by their remarkable catalytic and electronic properties. One area that garnered considerable attention is the fervent pursuit of layered TMDs as electrocatalysts for hydrogen evolution reaction (HER), driven by global efforts towards reducing carbon footprint and attaining hydrogen economy. This Tutorial Review captures the essence of electrochemistry of different classes of layered TMDs and metal chalcogenides across the period table and showcases their tuneable electrochemical and HER catalytic attributes that are governed by the elemental composition, structure and anisotropy.

Nonconductive layered hexagonal boron nitride exfoliation by bipolar electrochemistry.

Boron nitride (h-BN), which is an isoelectronic analogue of graphite, has received immense attention due to its unique physical and chemical properties. Numerous methods have been developed to isolate few-layered h-BN nanosheets. These include chemical vapour deposition, solution-based exfoliation and ball-milling amongst others.

Tunable Pt-MoS Hybrid Catalysts for Hydrogen Evolution.

Platinum (Pt)-based materials are inevitably among the best-performing electrocatalysts for hydrogen evolution reaction (HER). MoS was suggested to be a potent HER catalyst to replace Pt in this reaction by theoretical modeling; however, in practice, this dream remains elusive. Here we show a facile one-pot bottom-up synthesis of Pt-MoS composites using electrochemical reduction in an electrolytic bath of Pt precursor and ammonium tetrathiomolybdate under ambient conditions.

Inverse Opal-like Porous MoSe Films for Hydrogen Evolution Catalysis: Overpotential-Pore Size Dependence.

Transition metal dichalcogenides (TMDs) are prized as electrocatalysts for hydrogen evolution reaction (HER). Common TMD syntheses entail conditions of high temperatures and reagents that are detrimental to the environment. The electrochemical synthesis of TMDs is advocated as a viable alternative to the conventional synthetic procedures in terms of simplicity, ecological sustainability, and versatility of deposition on various surfaces at room temperature.

Morphological Effects and Stabilization of the Metallic 1T Phase in Layered V-, Nb-, and Ta-Doped WSe for Electrocatalysis.

Layered transition-metal dichalcogenides (TMDs) are valued for their electrocatalytic properties toward the hydrogen-evolution reaction (HER) and oxygen-reduction reaction (ORR). One effective strategy to activate the electrocatalytic properties of TMDs is through doping. The optimistic outlook of doped-MoS as an electrocatalyst witnessed in previous reports spurred us to examine the effect of doping WSe with Group 5 transition-metal species, namely V, Nb, and Ta, in aspects of inherent electroactivities and catalysis.

Unconventionally Layered CoTe and NiTe as Electrocatalysts for Hydrogen Evolution.

Two members of the transition metal ditelluride family, CoTe and NiTe , exist in multiple structures encompassing marcasite-, pyrite- and CdI related structures. The allotrope modification is influenced by weak changes in stoichiometry and synthesis. It is crucial to emphasize that the CdI structure type is manifested by NiTe while the CoTe adopts a related structure for a non-stoichiometric composition with ratio below 1:1.

2H → 1T Phase Change in Direct Synthesis of WS Nanosheets via Solution-Based Electrochemical Exfoliation and Their Catalytic Properties.

Metallic 1T-WS has various interesting properties such as increased density of catalytically active sites on both the basal planes and edges as well as metallic conductivity which allows it to be used in applications such as biosensing and energy devices. Hence, it is highly beneficial to develop a simple, efficient, and low-cost synthesis method of 1T-WS nanosheets from commercially available bulk 2H-WS. In this study, we reported WS nanosheets synthesized directly from bulk WS via solution-based electrochemical exfoliation with bipolar electrodes and investigated their electrocatalytic performances toward hydrogen evolution and oxygen reduction reactions.

Layered Noble Metal Dichalcogenides: Tailoring Electrochemical and Catalytic Properties.

Owing to the anisotropic nature, layered transition metal dichalcogenides (TMDs) have captured tremendous attention for their promising uses in a plethora of applications. Currently, bulk of the research is centered on Group 6 TMDs. Layered noble metal dichalcogenides, in particular the noble metal tellurides, belong to a subset of Group 10 TMDs, wherein the transition metal is a noble metal of either palladium or platinum.

Graphene/Group 5 Transition Metal Dichalcogenide Composites for Electrochemical Applications.

In comparison to the extensive research and great success attained by Group 6 transition metal dichalcogenides (TMDs) as hydrogen evolution reaction (HER) electrocatalysts, there is limited research focused on metallic Group 5 TMDs for use as electrocatalysts for hydrogen evolution. Density functional theory calculations have pointed out that Group 5 TMDs are highly favorable for HER, especially vanadium disulfide. In this work, nanocomposites of graphene and Group 5 TMDs were synthesized by thermal exfoliation of graphene oxide/TMD precursors in an H S atmosphere or in a H atmosphere as a control.

The Origin of MoS Significantly Influences Its Performance for the Hydrogen Evolution Reaction due to Differences in Phase Purity.

Molybdenum disulfide (MoS ) is at the forefront of materials research. It shows great promise for electrochemical applications, especially for hydrogen evolution reaction (HER) catalysis. There is a significant discrepancy in the literature on the reported catalytic activity for HER catalysis on MoS .

Anti-MoS2 Nanostructures: Tl2S and Its Electrochemical and Electronic Properties.

Layered transition metal dichalcogenides are catalytically important compounds. Unlike the mounting interest in transition metal dichalcogenides such as MoS2 and WS2 for electrochemical applications, other metal chalcogenides with layered structure but different chemical composition have received little attention among the scientific community. One such example is represented by thallium(I) sulfide (Tl2S), a Group 13 chalcogenide, which adopts the peculiar anti-CdCl2 type structure where the chalcogen is sandwiched between the metal layers.

Catalytic and charge transfer properties of transition metal dichalcogenides arising from electrochemical pretreatment.

Layered transition metal dichalcogenides (TMDs) have been the center of attention in the scientific community due to their properties that can be tapped on for applications in electrochemistry and hydrogen evolution reaction (HER) catalysis. We report on the effect of electrochemical treatment of exfoliated MoS2, WS2, MoSe2 and WSe2 nanosheets toward the goal of activating the electrochemical and HER catalytic properties of the TMDs. In particular, electrochemical activation of the heterogeneous electron transfer (HET) abilities of MoS2, MoSe2 and WSe2 is achieved via reductive treatments at identified reductive potentials based on their respective inherent electrochemistry.

Precise tuning of the charge transfer kinetics and catalytic properties of MoS2 materials via electrochemical methods.

MoS2 has become particularly popular for its catalytic properties towards the hydrogen evolution reaction (HER). It has been shown that the metallic 1T phase of MoS2 , obtained by chemical exfoliation after lithium intercalation, possesses enhanced catalytic activity over the semiconducting 2H phase due to the improved conductivity properties which facilitate charge-transfer kinetics. Here we demonstrate a simple electrochemical method to precisely tune the electron-transfer kinetics as well as the catalytic properties of both exfoliated and bulk MoS2 -based films.

Fluorographites (CF(x))n exhibit improved heterogeneous electron-transfer rates with increasing level of fluorination: towards the sensing of biomolecules.

Halogenated sp(2) materials are of high interest owing to their important electronic and electrochemical properties. Although methods for graphite and graphene fluorination have been extensively researched, the fundamental electrochemical properties of fluorinated graphite are not well established. In this paper, the electrochemistry of three fluorographite materials of different carbon-to-fluorine ratio were studied: (CF(0.