Interface Effects in the Stability of 2D Silica, Silicide, and Silicene on Pt(111) and Rh(111)
[1];
[1];
[3];
[4]
- Technical Univ. of Munich, Garching (Germany)
- Univ. of Alberta, Edmonton, AB (Canada)
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
- Technical Univ. of Munich, Garching (Germany); Univ. of Munich (Germany)
Ultrathin two-dimensional silica films have been suggested as highly defined conductive models for fundamental studies on silica-supported catalyst particles. Key requirements in this context are closed silica films that isolate the gas phase from the underlying metal substrate and stability under reaction conditions. Here, we present silica bilayer films grown on Pt(111) and Rh(111) and characterize them by scanning tunneling microscopy and X-ray photoelectron spectroscopy. We provide the first report of silica bilayer films on Rh(111) and have further successfully prepared fully closed films on Pt(111). Interestingly, surface and interface silicide phases play a decisive role in both cases: On platinum, closed films can be stabilized only when silicon is deposited in excess, which results in an interfacial silicide or silicate layer. We show that these silica films can also be grown directly from a surface silicide phase. In the case of rhodium, the silica phase is less stable and can be reduced to a silicide in reductive environments. Though similar in appearance to the "silicene" phases that have been controversially discussed on Ag(111), we conclude that an interpretation of the phase as a surface silicide is more consistent with our data. Finally, we show that the silica film on platinum is stable in 0.8 mbar CO but unstable at elevated temperatures. We thus conclude that these systems are only suitable as model catalyst supports to a limited extent.
- Research Organization:
- Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES), Scientific User Facilities Division; German Research Foundation (DFG); European Research Council (ERC); USDOE
- Grant/Contract Number:
- AC02-05CH11231; 2089/1-390776260; 850764; AC02- 05CH11231
- OSTI ID:
- 2350863
- Alternate ID(s):
- OSTI ID: 2406224
- Journal Information:
- ACS Applied Materials and Interfaces, Vol. 16, Issue 21; ISSN 1944-8244
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Enabling direct silicene integration in electronics: First principles study of silicene on NiSi2(111)
Preparation and structure of 1--8 monolayer thick epitaxial iron oxide films grown on Pt(111)