A. Badri et al., USE OF METHANOL AS AN IR MOLECULAR PROBE TO STUDY THE SURFACE CHLORINATION OF CERIA, Journal of the Chemical Society. Faraday transactions, 93(11), 1997, pp. 2121-2124
Citations number
16
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
Ceria has been chlorinated either by CCl4 treatment at 473 K or by imp
regnation with an aqueous HCl solution and the surface studied by IR s
pectroscopy using methanol as a probe. It was shown that methanol was
molecularly adsorbed on the CCl4-treated ceria, being H bonded to Cl-
surface species and O bonded to reduced Ce3+ surface cations. This ass
umes the reductive surface substitution of O2- species by Cl- ions dur
ing the CCl4 treatment with the formation of CeOCl species (Ce-III). W
ith the HCl-impregnated ceria sample, methanol was either molecularly
adsorbed or dissociated into methoxy species, indicating a mainly unre
duced (Ce-IV) surface that is homogeneously chlorinated by HCl-chemiso
rption. The importance of CeOCl surface species was further evidenced
when methanol was adsorbed on a reduced Pd/CeO2 catalyst prepared from
the PdCl2 precursor.