CO2 Adsorption, Diffusion and Electron-Induced Chemistry on Rutile TiO2(110) – A Low-Temperature Scanning Tunneling Microscopy Study

Journal Article · Thu Jun 23 04:00:00 EDT 2011 · Journal of Physical Chemistry C

OSTI ID:1025485

Sutter, P; Acharya, D P; Camillone, III, N

Low-temperature scanning tunneling microscopy (STM) has been used to study the adsorption of CO{sub 2} on rutile TiO{sub 2}(110) from 80 to 180 K. For low CO{sub 2} doses, two molecular adsorption sites with different binding energies are identified, which are effectively isolated from one another by an apparent activation barrier to their interconversion. We identify the less tightly bound adsorption site as CO{sub 2} adsorbed atop 5-fold coordinated titanium surface atoms (Ti{sub 5f}), without binding preferentially near oxygen vacancies. CO{sub 2} desorption from Ti{sub 5f} occurs at 140 K. The more strongly bound site involves molecular CO{sub 2} binding at bridging oxygen vacancies (V{sub O,br}). We observe two distinct configurations of V{sub O,br} bound CO{sub 2} molecules. Despite its being bound to the vacancy, CO{sub 2} does not dissociate thermally but remains intact up to the desorption temperature of {approx}175 K. At an elevated tunneling bias, the STM tip can selectively dissociate these CO{sub 2} molecules and thus trigger the healing of individual V{sub O,br}. At higher coverage, CO{sub 2} adsorption occurs predominantly at the more abundant Ti{sub 5f} sites, with the distribution of CO{sub 2} molecules being determined by interactions both along the [001] and [110] directions.

• Research Organization: Brookhaven National Laboratory (BNL) Center for Functional Nanomaterials
• Sponsoring Organization: DOE - OFFICE OF SCIENCE
• DOE Contract Number: AC02-98CH10886
• OSTI ID: 1025485
• Report Number(s): BNL--95279-2011-JA; KC020401H
• Journal Information: Journal of Physical Chemistry C, Journal Name: Journal of Physical Chemistry C Journal Issue: 24 Vol. 115; ISSN 1932-7447
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADSORPTION
ATOMS
CHEMISTRY
DESORPTION
DIFFUSION
DISTRIBUTION
HEALING
OXYGEN
RUTILE
SCANNING TUNNELING MICROSCOPY
TITANIUM
TUNNELING
VACANCIES
functional nanomaterials