Characterization of a Pt-Pd combustion catalyst on an alumina washcoat, with and without prior hydrothermal treatment of the washcoat
Artikel i vetenskaplig tidskrift, 1992

Two Pt/Pd catalysts on cordierite monoliths were prepared by impregnating two differently treated alumina washcoats with 10/micromol [Pt + Pd] per gram catalyst in the atomic ratio Pt/Pd = 4.0. Both washcoats were first thermally treated, calcined, for 2 h at 550C in air and one of them was additionally treated, hydrothermally, in 100% steam for 2 h at 814C. The hydrothermally treated catalyst was more active for complete oxidation of xylene in air: its light-off temperature was 232C compared to 259C for the sample calcined only. To explain this higher activity, both catalysts were characterized by BET surface area, pore-size distribution, hydrogen chemisorption, X-ray diffraction, TEM/STEM/EDS and low-energy ion scattering spectroscopy (LEIS). The catalyst with a hydrothermally treated washcoat had 30% lower surface area, larger alumina crystal size, higher degree of crystallization of alumina and larger average catalyst pore size (11 nm vs. 6 nm), than the one with the washcoat, treated only thermally. The LEIS results indicated a surface enrichment of Pd on both catalysts. The Pt signal in LEIS was higher for the hydrothermally treated sample.

xylene oxidation

combustion catalyst

light-off temperature

Pt-Pd/alumina

hydrothermal treatment

TEM/STEM/EDS

LEIS

Författare

Magnus Skoglundh

Institutionen för teknisk kemi

Lars Löwendahl

Institutionen för teknisk kemi

Govind Menon

Institutionen för teknisk kemi

Bertil Stenbom

Institutionen för fysik

Jean-Paul Jacobs

Otto van Kessel

Hidde Brongersma

Catalysis Letters

1011-372X (ISSN) 1572-879X (eISSN)

Vol. 13 27-38

Drivkrafter

Hållbar utveckling

Styrkeområden

Nanovetenskap och nanoteknik

Energi

Materialvetenskap

Ämneskategorier

Kemiteknik

DOI

10.1007/BF00770944