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Title: Selective growth of Al2O3 on size-selected platinum clusters by atomic layer deposition

Abstract

In heterogeneous catalysis, atomic layer deposition (ALD) has been developed as a tool to stabilize and reduce carbon deposition on supported nanoparticles. Here, we discuss use of high vacuum ALD to deposit alumina films on size-selected, sub-nanometer Pt/SiO2 model catalysts. Mass-selected Pt24 clusters were deposited on oxidized Si(100), to form model Pt24/SiO2 catalysts with particles shown to be just under 1 nm, with multilayer three dimensional structure. Alternating exposures to trimethylaluminum and water vapor in an ultra-high vacuum chamber were used to grow alumina on the samples without exposing them to air. The samples were probed in situ using X-ray photoelectron spectroscopy (XPS), low-energy ion scattering spectroscopy (ISS), and CO temperature-programmed desorption (TPD). Additional samples were prepared for ex situ experiments using grazing incidence small angle xray scattering spectroscopy (GISAXS). Alumina growth is found to initiate at least 60 times more efficiently at the Pt24 cluster sites, compared to bare SiO2/Si, with a single ALD cycle depositing a full alumina layer on top of the clusters, with substantial additional alumina growth initiating on SiO2 sites surrounding the clusters. As a result, the clusters were completely passivated, with no exposed Pt binding sites.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
Air Force Research Laboratory (AFRL) - Air Force Office of Scientific Research (AFOSR)
OSTI Identifier:
1568770
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article
Journal Name:
Surface Science
Additional Journal Information:
Journal Volume: 691
Country of Publication:
United States
Language:
English

Citation Formats

Gorey, Timothy J., Dai, Yang, Anderson, Scott L., Lee, Sungsik, Lee, Sungwon, Seifert, Soenke, and Winans, Randall E. Selective growth of Al2O3 on size-selected platinum clusters by atomic layer deposition. United States: N. p., 2020. Web. doi:10.1016/j.susc.2019.121485.
Gorey, Timothy J., Dai, Yang, Anderson, Scott L., Lee, Sungsik, Lee, Sungwon, Seifert, Soenke, & Winans, Randall E. Selective growth of Al2O3 on size-selected platinum clusters by atomic layer deposition. United States. doi:10.1016/j.susc.2019.121485.
Gorey, Timothy J., Dai, Yang, Anderson, Scott L., Lee, Sungsik, Lee, Sungwon, Seifert, Soenke, and Winans, Randall E. Wed . "Selective growth of Al2O3 on size-selected platinum clusters by atomic layer deposition". United States. doi:10.1016/j.susc.2019.121485.
@article{osti_1568770,
title = {Selective growth of Al2O3 on size-selected platinum clusters by atomic layer deposition},
author = {Gorey, Timothy J. and Dai, Yang and Anderson, Scott L. and Lee, Sungsik and Lee, Sungwon and Seifert, Soenke and Winans, Randall E.},
abstractNote = {In heterogeneous catalysis, atomic layer deposition (ALD) has been developed as a tool to stabilize and reduce carbon deposition on supported nanoparticles. Here, we discuss use of high vacuum ALD to deposit alumina films on size-selected, sub-nanometer Pt/SiO2 model catalysts. Mass-selected Pt24 clusters were deposited on oxidized Si(100), to form model Pt24/SiO2 catalysts with particles shown to be just under 1 nm, with multilayer three dimensional structure. Alternating exposures to trimethylaluminum and water vapor in an ultra-high vacuum chamber were used to grow alumina on the samples without exposing them to air. The samples were probed in situ using X-ray photoelectron spectroscopy (XPS), low-energy ion scattering spectroscopy (ISS), and CO temperature-programmed desorption (TPD). Additional samples were prepared for ex situ experiments using grazing incidence small angle xray scattering spectroscopy (GISAXS). Alumina growth is found to initiate at least 60 times more efficiently at the Pt24 cluster sites, compared to bare SiO2/Si, with a single ALD cycle depositing a full alumina layer on top of the clusters, with substantial additional alumina growth initiating on SiO2 sites surrounding the clusters. As a result, the clusters were completely passivated, with no exposed Pt binding sites.},
doi = {10.1016/j.susc.2019.121485},
journal = {Surface Science},
number = ,
volume = 691,
place = {United States},
year = {2020},
month = {1}
}