Shahid Iqbal
Xi'an Jiaotong University,China
Title: Controlled Synthesis and Layer-Number-Dependent Catalytic Properties of Few-layered MoS2/CdS van der Waals heterostructures for Efficient Photocatalytic H2 Evolution
Biography
Biography: Shahid Iqbal
Abstract
In a typical photocatalytic reaction, efficient solar light harvesting and charge generation, as well as effective charge transport, are key factors that determine the efficiency of the photocatalytic system for H2 production. Atomically layered heterostructures have attracted significant research interest due to their unique layer-dependent catalysis and electronic properties. Previous studies have reported that the catalytic properties of MoS2 layered materials are highly dependent on the number of layers, and the difficulty of controlling the number of layers over a substrate has been a bottleneck for widespread use. Therefore, developing a simple, facile and environmentally friendly method to fabricate van der Waals heterostructures (vdWHs) with precisely controlled MoS2 layers for achieving highly efficient H2 generation is still a challenge. Here we report for the first time that the H2 bubbles generated by photocatalytic water splitting are effective in the layer-by-layer exfoliation of MoS2 nanocrystals (NCs) into few layers (Figure 1). The as obtained few layers can be in situ assembled with CdS nanosheets (NSs) into vdWHs of few-layered MoS2/CdS NSs which, in turn, are effective in charge separation and transfer, leading to enhanced photocatalytic H2 production activity. The few-layered MoS2/CdS vdWHs exhibited a H2 evolution rate of 140 mmol g(CdS)-1 h-1 and achieved an apparent quantum yield of 66% at 420 nm. This study provides a new strategy for the design of noble-metal-free few-layered MoS2/CdS vdWH systems for photocatalytic H2 generation. We believe that this bubble exfoliation strategy can be extended to a range of other layered transition metal dichalcogenide compounds.