A New Dynamic Approach for N2O Decomposition by Pre-reduced Rh/CeZrOx Catalysts

Abstract

This study deals with the catalytic decomposition of N2O into harmless N2 and O2, in view of its potential application to decrease the pollution from internal combustion engines. The key of this work was to pre-reduce a Rh/CeZrOx catalyst under a H2 based atmosphere, in order to enhance the amount of oxygen vacancies in the ceria-based support. The results demonstrated that both, Rh species and oxygen vacancies of the ceria-based support catalyze the N2O decomposition reaction. However, the presence of high concentrations of H2O and O2 strongly inhibited the catalytic activity. Nevertheless, small O2 concentrations maintained the performance. Therefore, the pre-reduced Rh/CeZrOx could be potentially used for the reduction of N2O emitted by internal combustion engines working in stoichiometric conditions. In addition, a short injection of a reducing agent (e. g. H2) allowed to partially recover the initial catalytic activity of the system. All in all, this study proposes a new potential approach to mitigate the overall N2O greenhouse gas emissions.