High-Temperature Abatement of N₂O over FeOx/CeO₂-Al₂O₃ Catalysts: The Effects of Oxygen Mobility

Abstract

CeO2-Al2O3 oxides prepared by co-precipitation (Ce+Al) or CeOx precipitation onto Al2O3 (Ce/Al) to obtain dispersed CeO2 and samples with further supported FeOx (2.5–9.9 weight% in terms of Fe) were characterized by XRD, XPS, DDPA and Raman. Fe/Ce/Al samples with lower surface concentrations of Fe3+ were substantially more active in N2O decomposition at 700–900 °C. It was related to higher oxygen mobility, as estimated from 16O/18O exchange experiments and provided by preferential exposing of (Fe-)Ce oxides. Stabilization of some Ce as isolated Ce3+ in Fe-Ce-Al mixed oxides dominating in the bulk and surface layers of Fe/(Ce + Al) samples retards the steps responsible for fast additional oxygen transfer to the sites of O2 desorption.

Keywords

• N₂O decomposition
• Fe-Ce-Al mixed oxide
• oxygen mobility