Surface acidity of silica-titania mixed oxides

Journal Article · Mon Jun 01 04:00:00 EDT 1992 · Journal of Catalysis; (United States)

OSTI ID:7181029

Odenbrand, C U.I.; Brandin, J G.M. ^[1]; Busca, G ^[2]

---

1. Lund Univ. (Sweden)
2. Univ. di Genova (Italy)

A study of the acidity of coprecipitated SiO[sub 2]-TiO[sub 2] oxides is presented. The amount of acidity has been determined by ammonia adsorption at 150 C. The acidity was also characterized by TPD of adsorbed ammonia and by infrared spectroscopy of various adsorbed probes, such as pivalonitrile, pyridine, ammonia, and n-butylamine. From the quantitative measurements of adsorption of ammonia and from TPD it was concluded that the SiO[sub 2]-TiO[sub 2] mixture can be regarded as a mechanical mixture of silica and titania. However, the IR investigation showed that Ti enters in small amounts into the silica framework. This results in formation of very strong Lewis acid sites, caused by incomplete tetrahedral coordination of Ti[sup 4[minus]] ions exposed on the surface.

• OSTI ID: 7181029
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 135:2; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
ABSORPTION SPECTROSCOPY
ADSORPTION
AMINES
AMMONIA
AZINES
CHALCOGENIDES
CONTROL
CRYSTAL STRUCTURE
DESORPTION
DISPERSIONS
ELECTROMAGNETIC RADIATION
HETEROCYCLIC COMPOUNDS
HYDRIDES
HYDROGEN COMPOUNDS
INFRARED RADIATION
INORGANIC ACIDS
LEWIS ACIDS
MICROSTRUCTURE
MIXTURES
NITRILES
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PYRIDINE
PYRIDINES
RADIATIONS
SILICON COMPOUNDS
SILICON OXIDES
SORPTION
SPECTROSCOPY
SURFACE PROPERTIES
TEMPERATURE CONTROL
TITANIUM COMPOUNDS
TITANIUM OXIDES
TRANSITION ELEMENT COMPOUNDS