Catalytic Properties of CexZr1–xO2 Prepared Using a Template in the Oxidation of COстатья
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Дата последнего поиска статьи во внешних источниках: 2 декабря 2016 г.
Аннотация:The catalytic action in CO oxidation over double oxides CexZr1 – xO2 prepared using pine sawdust
and cetyltrimethylammonium bromide (CTAB) as templates is compared. It is found by means of SEM and
the low-temperature adsorption of N2 that biomorphic oxides reproduce the macropore structure of the template.
It is shown via XRD and Raman spectroscopy that all samples contained mixed ceria-zirconia oxide.
The double oxides form a cubic phase with a lattice of the fluorite type at a ratio of Ce : Zr = 4, regardless of the nature of the template; when Ce : Zr = 1, the biomorphic mixed oxide forms a tetragonal phase. According to Raman spectroscopy and X-ray diffraction it was shown that the distortion of the oxygen sublattice is higher for biomorphic samples. Energy dispersive analysis shows that Ca impurities were present in the biomorphic samples, introducing additional distortions in the lattice of double oxide and leading to the formation of anionic vacancies. It is found that when Ce : Zr = 4, the conversion of CO on biomorphic oxide in the range of 100–350°C is stronger than that observed for CexZr1 – xO2 (CTAB); reducing the Ce : Zr ratio in the biomorphic sample to 1 results in a marked decrease in CO conversion at 100–200°C. It is concluded that these differences are due to changes in the mobility of the lattice oxygen.