Pt-147 Nanoclusters Soft-Landed on WS2 Nanosheets for Catalysis and Energy Harvesting

Understanding the interaction between metal nanoclusters and two-dimensional (2D) layered materials presents a route toward the creation and tuning of hybrid materials. Here, we synthesize hybrid materials composed of mass-selected platinum nanoclusters produced using a magnetron sputtering gas aggregation cluster beam source with a lateral time-of-flight mass filter (mass resolution M/Delta M = 20) and large-area tungsten disulfide (WS2) 2D atomic layers. We employ aberration-corrected scanning transmission electron microscopy (STEM) in high-angle annular dark-field (HAADF) mode and micro-Raman spectroscopy to study the interaction between Pt-147 and suspended WS2 atomic layers. HAADF-STEM analysis reveals that soft-landed Pt-147 nanoclusters are situated on top of few-layered WS2 stacks, rather than being embedded or pinned. We observed a red shift in both E-2g and A(1g) modes and striking enhancement of A(1g) mode in the micro-Raman signatures of WS2, which provide evidence that Pt-147 clusters are soft-landed on the WS2 basal plane without disrupting the crystalline structure of the WS2 and of charge transfer from Pt-147 to WS2, respectively. In contrast, the measured change in line width of the E-2g mode of WS2 reveals a strong interaction between Pt-147 and WS2 layers. Direct evidence for the relative stability of Pt-147 clusters on WS2 is assessed by position-dependent Raman profiling and real-time HAADF-STEM imaging. Our approach offers a novel route to the controlled incorporation of size-selected nanoclusters on the 2D WS2 basal plane for catalysis and energy harvesting device applications.