Interaction of HCOOH with stoichiometric and reduced SrTiO{sub 3}(100) surfaces

Journal Article · Sat Jul 01 04:00:00 EDT 2000 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.582442· OSTI ID:20217059

Wang, Li-Qiong ^[1]; Ferris, K F ^[1]; Herman, G S ^[1]; Engelhard, M H ^[1]

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1. Environmental and Health Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

Interaction of formic acid with stoichiometric (TiO{sub 2}-terminated) and reduced SrTiO{sub 3}(100) surfaces has been investigated using temperature programmed desorption (TPD), and x-ray photoelectron spectroscopy (XPS). Formic acid was dissociated to form formate and a surface proton below 250 K on both stoichiometric and reduced SrTiO{sub 3}(100) surfaces. Formate was decomposed primarily through dehydration to produce CO and H{sub 2}O, instead of through dehydrogenation to produce CO{sub 2} and H{sub 2}, on both surfaces. Formaldehyde produced from decomposition of formate was also observed on both surfaces. On stoichiometric surfaces, formaldehyde was produced through bimolecular coupling of two formates on low-coordination Ti cation sites. However, on the reduced surface, formaldehyde formation involves the reduction of surface formates through the oxidation of reduced Ti cations. XPS results show that surface defects on reduced SrTiO{sub 3}(100) surfaces were reoxidized significantly upon exposure to 30 L HCOOH at 300 K, in contrast to defects on reduced TiO{sub 2}(110) surfaces where no reduction in defect intensity was observed under identical conditions. The TPD peak of formaldehyde on a reduced SrTiO{sub 3}(100) surface is shifted to lower temperature and is significantly broader (down to below 300 K) compared to on the stoichiometric surface. The adsorption and decomposition of HCOOH on SrTiO{sub 3}(100) surfaces are compared with those on TiO{sub 2} surfaces. (c) 2000 American Vacuum Society.

• OSTI ID: 20217059
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Journal Name: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films Journal Issue: 4 Vol. 18; ISSN 0734-2101; ISSN JVTAD6
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ADSORPTION
CRYSTAL DEFECTS
DESORPTION
EXPERIMENTAL DATA
FORMIC ACID
OXIDATION
PHOTOELECTRON SPECTROSCOPY
SELECTIVE CATALYTIC REDUCTION
STOICHIOMETRY
STRONTIUM OXIDES
SURFACES
TITANIUM OXIDES