Next Generation Automotive DeNO_x Catalysts: Ceria What Else?

Temporal analysis of products (TAP) was used to study NO reduction to N₂ over H₂ and C₃H₆-reduced La-Zr doped ceria at 560 °C. (La-Zr doped) ceria is found to be capable of fuel oxidation and NO reduction. NO dissociates on oxygen anion defects, thereby refilling these vacancies with oxygen anions and forming N₂. The carbonaceous deposits, in case the catalyst was reduced by C₃H₆, are oxidized by oxygen species originating from lattice oxygen. This recreates oxygen anion defects, which enables substantial additional NO reduction. These findings may open a new perspective on the understanding of DeNO_x by hydrocarbons.