Title: Growth and structural studies of In/Au(111) alloys and InO_x/Au(111) inverse oxide/metal model catalysts

Abstract

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 InO_x/Au(111) inverse model catalysts. Here, our study reveals distinct morphological differences between In/Au(111) and InO_x/Au(111), and the InO_x 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 InO_x/Au(111) systemsmore » which contain various sizes of InO_x aggregates (from 0.7 to 10 nm). On the other hand, InO_x/Au(111) surfaces prepared by vapor deposition of In at 550 K in an O₂ background exhibit highly dispersed and uniformly small InO_x particles (~1 nm). Both InO_x systems were confirmed to be partially oxidized by XPS.« less

Authors:

Kang, Jindong  ^[1];

• Search DOE PAGES for author "Kang, Jindong"
• Search DOE PAGES for ORCID "0000-0002-0292-7358"

Mahapatra, Mausumi ^[2]; Rui, Ning ^[2]; Orozco, Ivan ^[1]; Shi, Rui ^[1]; Senanayake, Sanjaya D. ^[2]; Rodriguez, José A.  ^[3]

• Search DOE PAGES for author "Rodriguez, José A."
• Search DOE PAGES for ORCID "0000-0002-5680-4214"

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+ Show Author Affiliations

1. State Univ. of New York (SUNY), Stony Brook, NY (United States)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)
3. State Univ. of New York (SUNY), Stony Brook, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)

Publication Date:

Mon Feb 03 00:00:00 EST 2020

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1633598

Alternate Identifier(s):

OSTI ID: 1596892

Report Number(s):

BNL-216032-2020-JAAM
Journal ID: ISSN 0021-9606; TRN: US2201384

Grant/Contract Number:  

SC0012704

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Chemical Physics

Additional Journal Information:

Journal Volume: 152; Journal Issue: 5; Journal ID: ISSN 0021-9606

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, 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