NiO--CeO2 and NiO--CeO2--ZrO2 catalysts have been synthesized,
electrochemically characterized (Mott-Schottky (MS) measurements
and Electrochemical Impedance Spectroscopy), physicochemically
characterized (by N2 adsorption, XRD, Transmission
Electron Microscopy and XPS) and tested in the N2O assisted
ethane oxydehydrogenation. The use of low Zr-loadings (Zr/
Ce=0.1 at. ratio) has led to the optimal results in the ethylene
production, improving those obtained by the Zr-free NiO--CeO2
catalyst. However, high Zr-loadings have meant a decrease in
the olefin production. The catalytic results obtained have been
explained considering the amount of oxygen vacancies, the
crystalline phases formed and, especially, the nature of the
surface Ni species. Importantly, the use of N2O as an oxidizing
agent leads to a remarkable improvement in the selectivity to
the olefin compared to that obtained employing molecular O2.
Then, for a given ethane conversion the selectivity to ethylene
is ca. 15 points higher using N2O than using O2. Another
additional positive aspect of this NiO--CeO2--ZrO2 catalyst is its
high catalytic stability.
