The CeO2-modified ZrO2 support was impregnated in an aqueous solution of ammonium heptamolybdate to achieve a loading of
8wt.% Mo. This material (Mo/Zr(Ce)) was characterized, in comparison with Mo/Zr, by X-ray diffraction, FT-IR and UV–VIS diffuse
reflectance spectroscopy as well as low temperature N2 adsorption and electrical conductivity measurements. The X-ray results showed
that the particles size of MoO3 on Zr(Ce) (24.7 nm) was lower than those on ceria free Zr (36.7 nm). The IR results indicated that a strong
interaction between Mo species and zirconia was recognized in the Mo/Zr(Ce) sample by the appearance of a new band at 858 cm−1
attributed to aMo–O–Zr linkage, which was not detected in the Mo/Zr sample. The UV–VIS spectra showed that both octahedral (291 nm)
and tetrahedral (249 nm) Mo6+ were detected in the Mo/Zr sample where tetrahedral arrangement (246 nm) was only adopted for Mo6+
in the Mo/Zr(Ce) sample. The addition of either Ce or Mo to zirconia causes a marked increase in the specific surface area of the samples.
The conductivity measurements showed that all samples exhibit a semiconducting behavior.
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