3R phase of MoS2 and WS2 outperforms the corresponding 2H phase for hydrogen evolution.

Rou Jun Toh,Jan Luxa,Zdeněk Sofer,Martin Pumera,David Sedmidubský

doi:10.1039/c6cc09952a

Abstract

Herein, we compare the bulk, 2H and 3R phases of two most prevalent TMD materials: MoS2 and WS2. The 3R phase outperforms its 2H phase counterpart in hydrogen evolution reaction catalysis and is even comparable with the exfoliated, 1T phase in the case of MoS2.

Highlights

We compare the bulk, 2H and 3R phases of two most prevalent Transition metal dichalcogenides (TMDs) materials: MoS2 and WS2
Previous works have reported a 2H - 1T phase transition when TMD materials are subjected to chemical exfoliation[23] and a comparison of the catalytic properties of 1T- and 2H-TMDs has shown that the exfoliated, metallic 1T phase performs as better catalysts than their bulk, semiconducting 2H counterparts for hydrogen evolution reaction (HER).[24]
We synthesized TMD materials (MoS2 and WS2) in their 3R phase, which allows us to perform a comparison of their HER catalytic activity with their corresponding 2H phase

Summary

Introduction

We compare the bulk, 2H and 3R phases of two most prevalent TMD materials: MoS2 and WS2. Previous works have reported a 2H - 1T phase transition when TMD materials are subjected to chemical exfoliation[23] and a comparison of the catalytic properties of 1T- and 2H-TMDs has shown that the exfoliated, metallic 1T phase performs as better catalysts than their bulk, semiconducting 2H counterparts for HER.[24] This was explained by the increased edge-exposed surface, reduced sheet size and enhanced electrical conductivity of the 1T phase.

Results

Conclusion