Synthesis and characterization of TiO{sub 2}--MgO mixed oxides prepared by the sol-gel method

Journal Article · Tue Aug 31 04:00:00 EDT 1999 · Langmuir

DOI:https://doi.org/10.1021/la9812931· OSTI ID:20000513

Lopez, T; Hernandez, J; Gomez, R; Bokhimi, X; Boldu, J L; Munoz, E; Novaro, O; Garcia-Ruiz, A

Titania-magnesia mixed oxides, with magnesia concentrations between 10 and 90 wt%, were prepared by using to sol-gel method with titanium n-butoxide and magnesium ethoxide as precursors. The mixed oxides were characterized with X-ray powder diffraction, BET nitrogen adsorption isotherms, electron spin resonance (ESR), and by testing their catalytic activity for 2-propanol and 2-butanol dehydration. Samples contained periclase, anatase, karooite (MgTi{sub 2}O{sub 5}), geikielite (MgTiO{sub 3}), and qandilite (Mg{sub 2}TiO{sub 4}). The BET specific surface area varied with magnesia concentration; the samples with 50 wt% MgO had the highest area, 211 m{sup 2}/g. Samples had paramagnetic centers that produced complex ESR spectra when many crystalline phases coexisted. For 2-propanol and 2-butanol decomposition, the activity and selectivity patterns of the mixed oxides were substantially different to those observed in pure TiO{sub 2} and pure MgO. This singular behavior should be a result of the structural defects created by the substitution of Mg{sup 2+} ions by Ti{sup 4+} cations in titania lattice, as well as by the interfaces created when several crystalline phases coexisted.

• Research Organization: Univ. Autonoma Metropolitana-Iztapalapa (MX)
• OSTI ID: 20000513
• Report Number(s): CONF-9808111--
• Journal Information: Langmuir, Journal Name: Langmuir Journal Issue: 18 Vol. 15; ISSN LANGD5; ISSN 0743-7463
• Country of Publication: United States
• Language: English

Related Subjects

10 SYNTHETIC FUELS
36 MATERIALS SCIENCE
BUTANOLS
CATALYTIC EFFECTS
CRYSTAL STRUCTURE
DEHYDRATION
MAGNESIUM OXIDES
PARAMAGNETISM
PROPANOLS
SOL-GEL PROCESS
SURFACE AREA
TITANIUM OXIDES