Microwave-Assisted vs. Conventional Hydrothermal Synthesis of MoS2 Nanosheets: Application towards Hydrogen Evolution Reaction

Getachew Solomon,Vittorio Morandi,Alberto Vomiero,Raffaello Mazzaro,Isabella Concina

doi:10.3390/cryst10111040

Getachew Solomon, Vittorio Morandi + Show 3 more

Open Access

https://doi.org/10.3390/cryst10111040

Copy DOI

Abstract

Molybdenum sulfide (MoS2) has emerged as a promising catalyst for hydrogen evolution applications. The synthesis method mainly employed is a conventional hydrothermal method. This method requires a longer time compared to other methods such as microwave synthesis methods. There is a lack of comparison of the two synthesis methods in terms of crystal morphology and its electrochemical activities. In this work, MoS2 nanosheets are synthesized using both hydrothermal (HT-MoS2) and advanced microwave methods (MW-MoS2), their crystal morphology, and catalytical efficiency towards hydrogen evolution reaction (HER) were compared. MoS2 nanosheet is obtained using microwave-assisted synthesis in a very short time (30 min) compared to the 24 h hydrothermal synthesis method. Both methods produce thin and aggregated nanosheets. However, the nanosheets synthesized by the microwave method have a less crumpled structure and smoother edges compared to the hydrothermal method. The as-prepared nanosheets are tested and used as a catalyst for hydrogen evolution results in nearly similar electrocatalytic performance. Experimental results showed that: HT-MoS2 displays a current density of 10 mA/cm2 at overpotential (−280 mV) compared to MW-MoS2 which requires −320 mV to produce a similar current density, suggesting that the HT-MoS2 more active towards hydrogen evolutions reaction.

Highlights

Two-dimensional (2D) transition-metal dichalcogenides (TMDs), such as MoS2, MoSe, WS2, have attracted much attention owing to their various applications
The nanosheets nanosheets obtained obtained by by microwave microwave methods methods show show thin thin and and uniform uniform morphology morphology confirmed confirmed by the SEM images
The as-prepared catalyst is catalyst compared in terms ofincrystal and catalytical

Summary

Introduction

Two-dimensional (2D) transition-metal dichalcogenides (TMDs), such as MoS2 , MoSe, WS2 , have attracted much attention owing to their various applications. As a low-cost and layer-type transition metal dichalcogenide, MoS2 is considered to be a promising electrocatalyst candidate for use in the hydrogen evolution reaction (HER) [1,2] supercapacitor [3], and in battery research areas [4,5]. The origin of the high catalytic under coordinated coordinated sulfur catalytic activity activity of of MoS. H for the edge edge that that possess possess aa metallic for conversion conversion into into molecular molecular hydrogen.

Methods

Discussion

Conclusion