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Title: Transition metal oxides deposited on rhodium and platinum: Surface chemistry and catalysis

Abstract

The surface chemistry and catalytic reactivity of transition metal oxides deposited on Rh and Pt substrates has been examined in order to establish the role of oxide-metal interactions in influencing catalytic activity. The oxides investigated included titanium oxide (TiOx), vanadium oxide (VOx), iron oxide (FeOx), zirconium oxide (ZrOx), niobium oxide (NbOx), tantalum oxide (TaOx), and tungsten oxide (WOx). The techniques used to characterize the sample included AES, XPS, LEED, TPD, ISS, and STM. After characterization of the surface in UHV, the sample was enclosed in an atmospheric reaction cell to measure the influence of the oxide deposits on the catalytic activity of the pure metal for CO and CO2 hydrogenation. The oxide deposits were found to strongly enhance the reactivity of the Rh foil. The rates of methane formation were promoted by up to 15 fold with the maximum in rate enhancement occurring at oxide coverages of approximately 0.5 ML. TiOx TaOx, and NbOx were the most effective promoters and were stable in the highest oxidation states during both reactions (compared to VOx, WOx, and FeOx). The trend in promoter effectiveness was attributed to the direct relationship between oxidation state and Lewis acidity. Bonding at the metal oxide/metal interface betweenmore » the oxygen end of adsorbed CO and the Lewis acidic oxide was postulated to facilitate C-O bond dissociation and subsequent hydrogenation. 192 refs.« less

Authors:
 [1]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
10186279
Report Number(s):
LBL-35954
ON: DE95000793; TRN: AHC29424%%62
DOE Contract Number:  
AC03-76SF00098
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: TH: Thesis (Ph.D.); PBD: Jul 1994
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 10 SYNTHETIC FUELS; 01 COAL, LIGNITE, AND PEAT; TITANIUM OXIDES; CATALYTIC EFFECTS; VANADIUM OXIDES; IRON OXIDES; TUNGSTEN OXIDES; ZIRCONIUM OXIDES; NIOBIUM OXIDES; TANTALUM OXIDES; CARBON MONOXIDE; METHANATION; CARBON DIOXIDE; CATALYSTS; CATALYST SUPPORTS; CONFIGURATION INTERACTION; CHEMICAL ANALYSIS; AUGER ELECTRON SPECTROSCOPY; PHOTOELECTRON SPECTROSCOPY; ELECTRON DIFFRACTION; ION SCATTERING ANALYSIS; MICROSCOPY; DESORPTION; TEMPERATURE CONTROL; EXPERIMENTAL DATA; 400201; 100200; 010408; CHEMICAL AND PHYSICOCHEMICAL PROPERTIES; PRODUCTION; C1 PROCESSES

Citation Formats

Boffa, Alexander Bowman. Transition metal oxides deposited on rhodium and platinum: Surface chemistry and catalysis. United States: N. p., 1994. Web. doi:10.2172/10186279.
Boffa, Alexander Bowman. Transition metal oxides deposited on rhodium and platinum: Surface chemistry and catalysis. United States. https://doi.org/10.2172/10186279
Boffa, Alexander Bowman. 1994. "Transition metal oxides deposited on rhodium and platinum: Surface chemistry and catalysis". United States. https://doi.org/10.2172/10186279. https://www.osti.gov/servlets/purl/10186279.
@article{osti_10186279,
title = {Transition metal oxides deposited on rhodium and platinum: Surface chemistry and catalysis},
author = {Boffa, Alexander Bowman},
abstractNote = {The surface chemistry and catalytic reactivity of transition metal oxides deposited on Rh and Pt substrates has been examined in order to establish the role of oxide-metal interactions in influencing catalytic activity. The oxides investigated included titanium oxide (TiOx), vanadium oxide (VOx), iron oxide (FeOx), zirconium oxide (ZrOx), niobium oxide (NbOx), tantalum oxide (TaOx), and tungsten oxide (WOx). The techniques used to characterize the sample included AES, XPS, LEED, TPD, ISS, and STM. After characterization of the surface in UHV, the sample was enclosed in an atmospheric reaction cell to measure the influence of the oxide deposits on the catalytic activity of the pure metal for CO and CO2 hydrogenation. The oxide deposits were found to strongly enhance the reactivity of the Rh foil. The rates of methane formation were promoted by up to 15 fold with the maximum in rate enhancement occurring at oxide coverages of approximately 0.5 ML. TiOx TaOx, and NbOx were the most effective promoters and were stable in the highest oxidation states during both reactions (compared to VOx, WOx, and FeOx). The trend in promoter effectiveness was attributed to the direct relationship between oxidation state and Lewis acidity. Bonding at the metal oxide/metal interface between the oxygen end of adsorbed CO and the Lewis acidic oxide was postulated to facilitate C-O bond dissociation and subsequent hydrogenation. 192 refs.},
doi = {10.2172/10186279},
url = {https://www.osti.gov/biblio/10186279}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 1994},
month = {Fri Jul 01 00:00:00 EDT 1994}
}

Thesis/Dissertation:
Other availability
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