Growth and structural studies of In/Au(111) alloys and InOx/Au(111) inverse oxide/metal model catalysts
- State Univ. of New York (SUNY), Stony Brook, NY (United States)
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- State Univ. of New York (SUNY), Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Indium oxide has received attention as an exciting candidate for catalyzing the CO2 hydrogenation to methanol due to its high selectivity (>80%). Compared to the extent of research on the activity of indium oxide-based powder catalysts, very little is known about the phenomena associated with the formation of surface alloys involving indium or the growth mechanism for indium oxide nanoparticles. In this report, scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) were employed to elucidate the growth mode, structure, and chemical state of In/Au(111) alloys and InOx/Au(111) inverse model catalysts. Here, our study reveals distinct morphological differences between In/Au(111) and InOx/Au(111), and the InOx structure also depends strongly on the preparation conditions. In/Au surface alloy systems with extremely low coverage (0.02 ML) form islands preferentially on the elbow sites of reconstructed Au(111) herringbone, regardless of hcp and fcc stacking. At higher coverage (0.1 ML), the In islands expand over the herringbone in the <110> direction and create two dimensional domain structures over the entire surfaces. Moreover, this 2D domain structure is disturbed by temperature with high dispersion of indium atoms observed during the annealing process. Oxidation of the In/Au(111) surface alloys with O2 at 550 K produces InOx/Au(111) systems which contain various sizes of InOx aggregates (from 0.7 to 10 nm). On the other hand, InOx/Au(111) surfaces prepared by vapor deposition of In at 550 K in an O2 background exhibit highly dispersed and uniformly small InOx particles (~1 nm). Both InOx systems were confirmed to be partially oxidized by XPS.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0012704
- OSTI ID:
- 1633598
- Alternate ID(s):
- OSTI ID: 1596892
- Report Number(s):
- BNL-216032-2020-JAAM; TRN: US2201384
- Journal Information:
- Journal of Chemical Physics, Vol. 152, Issue 5; ISSN 0021-9606
- Publisher:
- American Institute of Physics (AIP)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
Indium oxide
gold
catalysis
oxide chemistry and catalysis
scanning tunneling microscopy
hydrogenation process
catalysts and catalysis
hydrogen energy
vapor deposition
biofuels
x-ray photoelectron spectroscopy
nanoparticles
Auger electron spectroscopy