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Colloids and Surfaces A: Physicochem. Eng. Aspects 315 (2008) 147–155

Sol–gel synthesis and characterization of novel La, Mn and Fe doped
zirconia: Catalytic combustion activity of trichloroethylene
Javier Rivera De la Rosa a,∗ , Aracely Hernandez a , Fernando Rojas b , Juan Jos´ Ledezma a
e
a

Facultad de Ciencias Qu´micas, Universidad Aut´ noma de Nuevo Le´ n,Av. Universidad s/n, Cd. Universitaria,
ı
o
o
San Nicol´ s de los Garza, N.L. CP. 64450, Mexico
a
b Departamento de Qu´mica, Universidad Aut´ noma Metropolitana-Iztapalapa, P.O. Box 55-534, M´ xico D.F. 09340, Mexico
ı
o
e
Received 9 February 2007; received in revised form 18 July 2007; accepted 24 July 2007
Available online 3 August 2007

Abstract
Pure zirconia and novel 0.5 wt% La,Mn and Fe doped zirconia powders were synthesized by the sol–gel method. The samples obtained were
characterized by thermal analysis (DTA/TGA), infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The textural properties of the catalysts
were studied through N2 sorption isotherms measured at 77 K. In order to study the influence of the doping metals on the ZrO2 crystalline phaseformation, different doping metal loadings were employed. It was found that the ZrO2 monoclinic phase is favored at 800 ◦ C when using a La-Mn
doping combination, while the tetragonal structure was promoted by a La-Fe doping mixture. The morphology of the gel particles was seen to be
influenced by the nature of the doping metal; scanning electron microscopy served to observe this phenomenon.
Texturalanalysis by N2 sorption revealed that were obtained porous materials. The La-Fe zirconia catalyst resisted the high concentration
trichloroethylene flow and kept its activity as the temperature was increased. The catalytic activity tests showed that the ZrO2 tetragonal phase
stabilized by La, Fe doping agents significantly improved the catalytic combustion of trichloroethylene.
© 2007 Elsevier B.V.All rights reserved.
Keywords: Doped; Zirconia; Sol–gel; Trichloroethylene; Catalytic combustion; Porous materials

1. Introduction
Zirconia is one of the most studied ceramic materials due to
its outstanding thermal, mechanical and chemical stability; in
addition, acidic, basic, oxidizing and reducing surface properties make this oxide suitable for many catalytic processes [1–3].
Dependingon the preparation method and thermal treatment,
monoclinic, tetragonal, cubic, or a mixture of these phases can
be obtained. The most common method of preparation of ZrO2
is by pyrolysis from very pure zirconium chlorides or alkoxides [3]. At room temperature, the stable crystalline phase is
the monoclinic form and the reversible transformation to the
tetragonal phase occurs at 1100–1200 ◦C, the cubic structure is
only formed at 2373 ◦ C [4]. It has also been pointed out that
zirconium oxide is an interesting and useful catalytic support.
La-Mn and La-Fe perovskites supported on ZrO2 have shown
good performances during methane combustion and CO oxi-

∗

Corresponding author. Tel.: +52 8183294010; fax: +552 8183765375.
E-mail address: jarivera@fcq.uanl.mx (J.R. De la...