Tuning the catalytic functionality of transition metal dichalcogenides grown by chemical vapour deposition

Abstract

Nanomaterials have been widely investigated as high performance catalysts due to their extremely enhanced surface-to-volume ratio compared with bulk materials. Among the nanomaterials, transition metal dichalcogenides (TMDs) have attracted much interest and been studied as a good candidate for electrocatalysts due to the capability of tuning their catalytically active sites. One of the primary methods for the synthesis of TMDs is chemical vapour deposition (CVD), which enables the growth of high quality, large-area TMDs with uniform, atomically thin features and layer number controllability. In addition, the high degrees of freedom of CVD methods can provide effective routes for realizing various morphologies and structures of the synthesized TMD films with versatile catalytic functionalities. This review is intended to deliver a focused overview of CVD growth routes of functional TMDs with catalytic functionality that enables the enhancement of their HER performances. Two growth strategies for the generation of catalytically active sites in functional TMDs are introduced. The first strategy is the activation of the TMD basal plane by creating additional defects, such as S vacancies, in the post-growth stage. The second is the effective production of catalytic edges by engineering the morphologies and structures of CVD-grown TMDs in the mid-growth stage. The resulting HER performances for each CVD growth route are also discussed. This review will provide insights for the design of synthetic schemes and catalytic systems of CVD-grown functional TMDs for high performance HER applications.