Nitrous oxide decomposition in a real nitric acid plant gas stream with a RhOx/Ce0.9Pr0.1O2/alumina catalyst

Abstract

Background: N2O is a powerful greenhouse gas emitted in nitric acid plants, and emission control technologies are required. Results: A 0.25%Rh/50%Ce0.9Pr0.1O2/γ-Al2O3 catalyst has been prepared and tested for N2O decomposition in a real nitric acid plant gas stream. The catalyst is active enough to achieve 100% N2O removal, maintaining a constant catalytic activity after 40 h operation without deactivating. Characterization of the fresh and used catalyst, using different techniques, revealed no changes during the N2O decomposition experiments: (i) XRD and Raman spectroscopy show the fluorite structure of the Ce–Pr mixed oxide before and after the catalytic tests, (ii) the crystal size of the Ce–Pr mixed oxide particles and the BET surface area of the catalyst is maintained, evidencing no sintering of ceria particles, (iii) H2-TPR indicates that the reducibility of the catalyst is similar before and after the catalytic tests, revealing chemical stability, and (iv) TEM and XPS analysis indicated the high stability of the rhodium particle size and oxidation state. Conclusion: An active and stable catalyst with formulation 0.25%Rh/50%Ce0.9Pr0.1O2/γ-Al2O3 has been prepared and successfully tested for N2O decomposition in a real nitric acid plant gas stream.