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/ΔM = 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 Pt147 and suspended WS2 atomic layers. HAADF-STEM analysis reveals that soft-landed Pt147 nanoclusters are situated on top of few-layered WS2 stacks, rather than being embedded or pinned. We observed a red shift in both E2g and A1g modes and striking enhancement of A1g mode in the micro-Raman signatures of WS2, which provide evidence that Pt147 clusters are soft-landed on the WS2 basal plane without disrupting the crystalline structure of the WS2 and of charge transfer from Pt147 to WS2, respectively. In contrast, the measured change in line width of the E2g mode of WS2 reveals a strong interaction between Pt147 and WS2 layers. Direct evidence for the relative stability of Pt147 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.
This work was supported financially by the HORIZON 2020, H2020 Marie-Skłodowska-Curie Actions (Grant Numbers: H2020-MSCA-IF-2017, 750929). Dr. Ravi K. Biroju acknowledges Prof. Richard E Palmer, Swansea University, and Dr. Shane Murphy, Technological University Dublin for their support. This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT, Ministry of Science and ICT) (Grant No. NRF-2020R1A2C2009378). We gratefully acknowledge Catherine Storey, Experimental officer, NPRL, for her assistance in some part of the sample preparation. We acknowledge Dr. Balakrishna Ananthoju and Prof. Robert A W Dryfe for doing XPS measurements. We thank Dr. Ziyou Li, NPRL, for helping with HAADF-STEM image analysis of WS2-Pt147 hybrids. Dr. Ravi K. Biroju would like to dedicate this paper to Dr. Ziyou Li, who passed away in December 2020.
- General Materials Science
- 2D materials
- gas-phase cluster-beam deposition
- physical vapor transport
- stacking sequence
- WS atomic layers
- mass-selected Pt nanoclusters
- high-angle annular dark field (HAADF)-scanning transmission electron microscopy (STEM)
ASJC Scopus subject areas
- Materials Science(all)