The morphology of mass selected ruthenium nanoparticles from a magnetron-sputter gas-aggregation source
- 504 Downloads
We have investigated the morphology of mass selected ruthenium nanoparticles produced with a magnetron-sputter gas-aggregation source. The nanoparticles are mass selected using a quadrupole mass filter, resulting in narrow size distributions and average diameters between 2 and 15 nm. The particles are imaged in situ by scanning electron microscopy and scanning tunneling microscopy (STM) as well as ex-situ using transmission electron microscopy (TEM). For each distribution of mass selected nanoparticles, the height determined by STM and the width determined by TEM are seen to be similar throughout the mass range investigated. The particles are found to have a well-defined morphology for diameters below approximately 6 nm. Larger nanoparticles are less well-defined having rough surfaces, unlike the equilibrium morphology determined from the Wulff construction. The morphology of the particles is, in general, believed to be determined by the conditions inside the gas-aggregation source and the morphology is retained as the particles are soft-landed on the substrate.
KeywordsHOPG Magnetron-sputter gas-aggregation source Mass selected nanoparticles Nanoparticle morphology Scanning tunneling microscopy Synthesis and characterization Transmission electron microscopy Ruthenium
This study was supported by the Danish National Research Foundation and the EU FWP7 Marie Curie Intra-European Fellowship ESRCN (PIEF-GA-2008- 220055). The use of facilities at the Center of Electron Nanoscopy (CEN) at DTU is acknowledged.
- Andersson MP, Abild-Pedersen F, Remediakis IN, Bligaard T, Jones G, Engbæk J, Lytken O, Horch S, Nielsen JH, Sehested J, Rostrup-Nielsen JR, Nørskov JK, Chorkendorff I (2008) Structure sensitivity of the methanation reaction: H2-induced CO dissociation on nickel surfaces. J Catal 255:6–19CrossRefGoogle Scholar
- Gavnholt J (2009) The structure of individual nanoparticles and hot electron assisted chemistry at surfaces. Dissertation, Technical University of DenmarkGoogle Scholar
- Gavnholt J, Schiøtz J (2008) Structure and reactivity of ruthenium nanoparticles. Phys Rev B 77:035404-1-035404-10Google Scholar
- Jones G, Jakobsen JG, Shim SS, Kleis J, Andersson MP, Rossmeisl J, Abild-Pedersen F, Bligaard T, Helveg S, Hinnemann B, Rostrup-Nielsen JR, Chorkendorff I, Sehested J, Nørskov JK (2008) First principles calculations and experimental insight into methane steam reforming over transition metal catalysts. J Catal 259:147–160CrossRefGoogle Scholar
- Moseler M, Häkkinen H, Landman U (2002) Supported magnetic nanoclusters: soft landing of Pd clusters on a MgO surface. Phys Rev Lett 89:176103-1–176103-4Google Scholar
- Zhang G, Yang D, Sacher E (2007) Structure and morphology of Co nanoparticles deposited onto highly oriented pyrolytic graphite. J Phys Chem 111:17200–17205Google Scholar