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Title: Probing Surface Sites of TiO2: Reactions with [HRe(CO)5] and [CH3Re(CO)5]

Abstract

Two carbonyl complexes of rhenium, [HRe(CO){sub 5}] and [CH{sub 3}Re(CO){sub 5}], were used to probe surface sites of TiO{sub 2} (anatase). These complexes were adsorbed from the gas phase onto anatase powder that had been treated in flowing O{sub 2} or under vacuum to vary the density of surface OH sites. Infrared (IR) spectra demonstrate the variation in the number of sites, including Ti{sup +3} {double_bond} OH and Ti{sup +4} {double_bond} OH. IR and extended X-ray absorption fine structure (EXAFS) spectra show that chemisorption of the rhenium complexes led to their decarbonylation, with formation of surface-bound rhenium tricarbonyls, when [HRe(CO){sub 5}] was adsorbed, or rhenium tetracarbonyls, when [CH{sub 3}Re(CO){sub 5}] was adsorbed. These reactions were accompanied by the formation of water and surface carbonates and removal of terminal hydroxyl groups associated with Ti{sup +3} and Ti{sup +4} ions on the anatase. Data characterizing the samples after adsorption of [HRe(CO){sub 5}] or [CH{sub 3}Re(CO){sub 5}] determined a ranking of the reactivity of the surface OH sites, with the Ti{sup +3}OH groups being the more reactive towards the rhenium complexes but the less likely to be dehydroxylated. The two rhenium pentacarbonyl probes provided complementary information, suggesting that the carbonate species originate frommore » carbonyl ligands initially bonded to the rhenium and from hydroxyl groups of the titania surface, with the reaction leading to the formation of water and bridging hydroxyl groups on the titania. The results illustrate the value of using a family of organometallic complexes as probes of oxide surface sites.« less

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
Sponsoring Org.:
DOE - OFFICE OF SCIENCE
OSTI Identifier:
1019741
Report Number(s):
BNL-95587-2011-JA
Journal ID: ISSN 0947-6539; TRN: US201115%%380
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Chemistry - A European Journal
Additional Journal Information:
Journal Volume: 16; Journal Issue: 37; Journal ID: ISSN 0947-6539
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION; ADSORPTION; CARBONATES; CARBONYLS; CHEMISORPTION; CHEMISTRY; FINE STRUCTURE; OXIDES; PROBES; REMOVAL; RHENIUM; RHENIUM COMPLEXES; SPECTRA; SPECTROSCOPY; WATER; national synchrotron light source

Citation Formats

Lobo-Lapidus, R, and Gates, B. Probing Surface Sites of TiO2: Reactions with [HRe(CO)5] and [CH3Re(CO)5]. United States: N. p., 2010. Web. doi:10.1002/chem.201000267.
Lobo-Lapidus, R, & Gates, B. Probing Surface Sites of TiO2: Reactions with [HRe(CO)5] and [CH3Re(CO)5]. United States. https://doi.org/10.1002/chem.201000267
Lobo-Lapidus, R, and Gates, B. 2010. "Probing Surface Sites of TiO2: Reactions with [HRe(CO)5] and [CH3Re(CO)5]". United States. https://doi.org/10.1002/chem.201000267.
@article{osti_1019741,
title = {Probing Surface Sites of TiO2: Reactions with [HRe(CO)5] and [CH3Re(CO)5]},
author = {Lobo-Lapidus, R and Gates, B},
abstractNote = {Two carbonyl complexes of rhenium, [HRe(CO){sub 5}] and [CH{sub 3}Re(CO){sub 5}], were used to probe surface sites of TiO{sub 2} (anatase). These complexes were adsorbed from the gas phase onto anatase powder that had been treated in flowing O{sub 2} or under vacuum to vary the density of surface OH sites. Infrared (IR) spectra demonstrate the variation in the number of sites, including Ti{sup +3} {double_bond} OH and Ti{sup +4} {double_bond} OH. IR and extended X-ray absorption fine structure (EXAFS) spectra show that chemisorption of the rhenium complexes led to their decarbonylation, with formation of surface-bound rhenium tricarbonyls, when [HRe(CO){sub 5}] was adsorbed, or rhenium tetracarbonyls, when [CH{sub 3}Re(CO){sub 5}] was adsorbed. These reactions were accompanied by the formation of water and surface carbonates and removal of terminal hydroxyl groups associated with Ti{sup +3} and Ti{sup +4} ions on the anatase. Data characterizing the samples after adsorption of [HRe(CO){sub 5}] or [CH{sub 3}Re(CO){sub 5}] determined a ranking of the reactivity of the surface OH sites, with the Ti{sup +3}OH groups being the more reactive towards the rhenium complexes but the less likely to be dehydroxylated. The two rhenium pentacarbonyl probes provided complementary information, suggesting that the carbonate species originate from carbonyl ligands initially bonded to the rhenium and from hydroxyl groups of the titania surface, with the reaction leading to the formation of water and bridging hydroxyl groups on the titania. The results illustrate the value of using a family of organometallic complexes as probes of oxide surface sites.},
doi = {10.1002/chem.201000267},
url = {https://www.osti.gov/biblio/1019741}, journal = {Chemistry - A European Journal},
issn = {0947-6539},
number = 37,
volume = 16,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 2010},
month = {Fri Jan 01 00:00:00 EST 2010}
}