N2O decomposition rhodium/ceria catalystsfrom principles to practical application

Résumé

This thesis presents the results of the study of Rh catalysts supported on CeO2 for the reaction of N2O decomposition. The emission of this gas to the atmosphere cause environmental problems that are described along with the main anthropogenic sources and the current European legislation for this greenhouse gas control. In this work a series of catalysts Rh, Pd and Pt supported on [gamma]-Al2O3, CeO2 and CeO2 doped with La or Pr, have been prepared, characterized and tested at a laboratory scale. The results show that the activity of the three noble metals studied follows the sequence Rh> Pd> Pt and the support plays a considerable effect on the catalysts activity. N2O decomposition mechanisms have been studied by using spectroscopic techniques and isotopic labeling tests for Rh/[gamma]-Al2O3 and Rh/CeO2 catalysts. In this study the results of experiments conducting at laboratory scale and at pilot plant (stream of gases from a nitric acid plant) obtained with the most promising catalyst (Rh/CeO2(Pr)) has been included. Finally, studying the effect of inhibitors such as H2O, O2 and NOx was also analyzed.