Au-MoS₂ Hybrids as Hydrogen Evolution Electrocatalysts

Abstract

Core-shell nanoparticles provide a unique morphology to exploit electronic interactions between dissimilar materials conferring them new or improved functionalities. MoS2 is a layered transitionmetal disulfide that has been studied extensively for the hydrogen evolution reaction (HER) but still suffers from low electrocatalytic activity due to its poor electronic conductivity. To understand the fundamental aspects of the MoS2-Au hybrids with regard to their electrocatalytic activity, a single to a few layers of MoS2 were deposited over Au nanoparticles via a versatile procedure that allows for complete encapsulation of Au nanoparticles of arbitrary geometries. High-resolution transmission electron microscopy of the Au@MoS2 nanoparticles provides direct evidence of the core-shell morphology and also reveals the presence of morphological defects and irregularities in the MoS2 shell that are known to be more active for HER than the pristine MoS2 basal plane.Electrochemical measurements show a significant improvement in the HER activity of Au@MoS2 nanoparticles relative to free-standing MoS2 or Au-decorated MoS2. The best electrochemical performance was demonstrated by the Au nanostars -the largest Au core employed hereencapsulated in an MoS2 shell. Density-functional theory calculations show that charge transfer occurs from the Au to the MoS2 layers, producing a more conductive catalyst layer and a better electrode for electrochemical HER. The strategies to further improve the catalytic properties of such hybrid nanoparticles are discussed.

Transition Metal Dichalcogenides for the Application of Pollution Reduction: A Review

“…Numerous works have discovered ways to enhance the HER performance of MoS 2 . Just to name a few, these works proposed to improve the HER activity by (i) coating the MoS 2 with metals (e.g., palladium [64], aluminum [65], gold [66], platinum [67], etc. ); (ii) using a novel electrochemical approach to deposit the MoS 2 nanosheet [68]; (iii) introducing the use promising support for the MoS 2 nanoparticles (e.g., multi-wall carbon nanotubes [69]); (iv) varying the choice of dispersion media used [70]; and (v) coupling with other electrocatalysts (e.g., molybdenum carbide [71]).…”

Shelling with MoS2: Functional CuS@MoS2 hybrids as electrocatalysts for the oxygen reduction and hydrogen evolution reactions

“…This morphology correlates the enhancement of the catalytic activity with the 3D structure and porosity of the MoS2 shell. It can be assumed that the core is more than a template to the MoS2 shell, [32] and CuS core offers additional benefits due to its unique properties for electron capture and transport. [37] Our previous study showed that the structure and activity of Cu2-xS@MoS2 nanooctahedra, with a single MoS2 shell, are closely connected with the atomic-scale structure of the interface.…”

“…Thus far, several core materials have been selected for encapsulation by MoS2. [26][27][28][29][30] The use of hybrid Au-MoS2 core-shell structures as model photocatalysts [23,24,31] and electrocatalysts [18,32] was recently reported. Our previous studies demonstrated that Au@MoS2 nanoparticles enhance the catalytic activity by the charge transfer from Au to MoS2 and by the strain within the MoS2 lattice as it embeds the curved Au nanoparticle.…”

Remarkable Enhancement of Catalytic Activity of Cu-Complexes in the Electrochemical Hydrogen Evolution Reaction (HER) by Using Triply-Fused Porphyrin

“…[3] In the past decade, substantial effort and time have been devoted towards finding cheap, efficient and robust catalysts comprised of earth-abundant elements for HER. [6,7] As a result, several transition metal complexes of earth-abundant elements like Fe, [8] Co, [9] Mo, [10] Cu [11] and Ni [12] have been recognized as active molecular electrocatalysts for HER. In addition to homogeneous systems, molecular catalysts immobilized on carbon nanotube-templated covalent frameworks, have also been identified as active catalysts for the proton reduction reaction in aqueous medium.…”