Morphology of Palladium Thin Film Deposited on a Two-Dimensional Bilayer Aluminosilicate
- 51 Downloads
The morphology of a thin palladium film deposited on bilayer Al0.35Si0.65O2/Ru(0001), previously proposed as a two-dimensional zeolite model, is investigated using a set of complementary spectroscopy and microscopy tools. Pd single atoms are known to penetrate the bilayer silica, but when a thick Pd film is deposited on the aluminosilicate case some of the metal remains on top of the bilayer oxide. Annealing this surface results in a decrease in the Pd/Si ratio seen in X-ray photoelectron spectroscopy, indicating either further permeation of Pd, or dewetting of surface Pd to form nanoparticles and leave aluminosilicate exposed. An interesting observation is that two very distinct morphologies are obtained for the film. On small narrow terraces, flat wetting films are produced, while on larger terraces Pd particles leaving a partially exposed bilayer aluminosilicate framework are obtained.
KeywordsThin film Surface science 2D-silica 2D-zeolite Catalysis Metal-support interaction
This research used resources of the Center for Functional Nanomaterials and the IOS, and ESM beamlines at the National Synchrotron Light Source II, which are U.S. DOE Office of Science User Facilities, at Brookhaven National Laboratory under Contract No. DE-SC0012704. J.Q. Zhong was supported by BNL LDRD Project No. 15-010. This work was supported as part of the Integrated Mesoscale Architectures for Sustainable Catalysis (IMASC), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under award #DE-SC0012573. We thank Dr. Zhongwei Dai for useful discussions.
- 14.Kaden WE, Büchner C, Lichtenstein L, Stuckenholz S, Ringleb F, Heyde M, Sterrer M, Freund H-J, Giordano L, Pacchioni G, Nelin CJ, Bagus PS (2014) Understanding surface core-level shifts using the Auger parameter: a study of Pd atoms adsorbed on ultrathin SiO2 films. Phys Rev B 89:115436CrossRefGoogle Scholar
- 19.Boscoboinik JA (2019) Chemistry in confined space through the eyes of surface science—2D porous materials. J Phys: Condens Matter 31:063001Google Scholar
- 22.Lewandowski AL, Schlexer P, Tosoni S, Gura L, Marschalik P, Büchner C, Burrall H, Burson KM, Schneider W-D, Pacchioni G, Heyde M (2018) Determination of silica and germania film network structures on Ru(0001) at the atomic scale. J Phys Chem C. https://doi.org/10.1021/acs.jpcc.8b07110 Google Scholar
- 29.Zhong J-Q, Kestell J, Waluyo I, Wilkins S, Mazzoli C, Barbour A, Kaznatcheev K, Shete M, Tsapatsis M, Boscoboinik JA (2016) Oxidation and reduction under cover: chemistry at the confined space between ultrathin nanoporous silicates and Ru(0001). J Phys Chem C. https://doi.org/10.1021/acs.jpcc.6b02851 Google Scholar
- 30.Kestell JD, Mudiyanselage K, Ye X, Nam C-Y, Stacchiola D, Sadowski J, Boscoboinik JA (2017) Stand-alone polarization-modulation infrared reflection absorption spectroscopy instrument optimized for the study of catalytic processes at elevated pressures. Rev Sci Instrum 88:105109CrossRefGoogle Scholar