INVESTIGADORES
BOIX Alicia Viviana
artículos
Título:
Preferential CO oxidation on Pt-Cu/Al2O3 catalysts with low Pt loadings
Autor/es:
GOMEZ, LETICIA; SOLLIER, BRENDA; MIZRAHI, MARTIN; RAMALLO LOPEZ, JOSE; MIRO, EDUARDO; BOIX, ALICIA
Revista:
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 39 p. 3719 - 3729
ISSN:
0360-3199
Resumen:
This work demonstrates that a small loading of Pt (0.2-0.5 wt.%)
selectively located at the
top of the Cu/Al2O3 solid is enough to obtain active
catalysts for the COPrOx reaction. The
characterizations of the catalysts prepared in this
work using different Pt:Cu ratios show
that the phases formed strongly depend on the Cu and
Pt loadings. For the samples with
4 wt.% of Cu, the formation of defective CuAl2O4-like
species is predominant, with Cu(2+)
occupying distorted sites in the alumina surface. For
the samples with 8 wt.% of Cu, CuO
and metallic Cu in the form of small crystals are
observed besides Cu(2+). For both 0.2 and
0.5 wt.% of Pt, some proportion of Cu-Pt alloy is found
which increased with the Cu
content. Metallic Pt particles are only observed by
EXAFS for the samples with a higher
loading of the noble metal.
The higher CO conversions at low temperatures were
obtained for the Pt0.5Cu8/Al2O3
sample, probably due to the simultaneous formation of
small Pt crystals in close contact
with CuO. The XPS results show that a strong surface
enrichment in Pt takes place in all the
samples. Thus, a small loading of the noble metal is
enough to obtain effective catalysts.
The surface Pt enrichment observed is most probably
due to the impregnation of the Pt salt
onto the Cu/Al2O3 solid, with a relatively low
calcination temperature (300 ºC) that prevents
the formation of bulky CuAl2O4
spinel crystals