Methane combustion of Pd/SiO{sub 2} sol gel catalysts

Journal Article · Thu Oct 01 04:00:00 EDT 1998 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1998.2164· OSTI ID:672473

Pecchi, G; Reyes, P; Concha, I ^[1]; Fierro, J L.G. ^[2]

---

1. Univ. de Concepcion (Chile). Facultad de Ciencias Quimicas
2. CSIC, Madrid (Spain). Inst. de Catalisis y Petroleoquimica

Surface properties and catalytic activity changes of Pd/SiO{sub 2} catalysts prepared by sol-gel processing have been investigated by evaluating the specific surface area, porosity, metal dispersion, surface acidity, and surface composition. As a comparison, Pd/SiO{sub 2} catalysts prepared by impregnation of SiO{sub 2} obtained by the sol-gel method were also studied. Both series of catalysts were tested in cycles of methane combustion. It has been found that the pH of gelation modifies strongly the porosity and surface area of the catalysts. However, no significant changes were observed in the metal dispersion. XPS results showed that for the catalysts obtained by the sol-gel procedure the Pd/Si surface atomic ratio does not change before or after the combustion cycle. However, in those catalysts prepared by the impregnation method, a significant decrease in the Pd/Si ratio was observed. The catalytic activity in the methane combustion under stoichiometric mixture of diluted CH{sub 4}/O{sub 2} was studied at different temperatures from 473 K up to the temperature required for a total conversion of all the catalysts. It was found that the activity is higher after their use in the catalytic reaction. This behavior is attributed to the presence of Pd{sub {delta}+} species which improve the catalytic activity.

• OSTI ID: 672473
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 179; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
33 ADVANCED PROPULSION SYSTEMS
54 ENVIRONMENTAL SCIENCES
AIR POLLUTION CONTROL
CATALYTIC COMBUSTORS
CATALYTIC EFFECTS
COMBUSTION
METHANE
PALLADIUM
PH VALUE
POROSITY
SILICON OXIDES
SURFACE AREA
VOLATILE MATTER