Surface reconstructions of LaCo_(1-X)Fe_xO3 at high temperature during N2O decomposition in realistic exhaust gas composition: Impact on the catalytic properties

摘要

This study is dedicated to the development of thermally stable LaCo_(1-X)Fe_xO3 perovskite based catalysts for the decomposition of N2O at medium and high temperature, in representative compositions of exhaust gas from ammonia burner in nitric acid plants. In these specific conditions, N2O coexists with a large amount of NO_x. Up to now, lab-scale investigations were usually restricted to low amount of NO_x and water while both can originate drastic changes in the catalytic performances related to activa-tion/deactivation phenomena. The impact of NO concentration in terms of activity and stability has been discussed at moderate temperature and correlated to extensive bulk and surface characterization from different techniques (X-ray diffraction, Raman spectroscopy, XPS, Mossbauer spectroscopy, Tof-SIMS). It was found that the catalytic performances in terms of activity and stability depend on the relative concentration of Co with the best performances recorded on LaCo_(0.2)Fe_(0.8)O3.