The direct decomposition of NO into N2 and O2 over copper doped Ba3Y4O9

Abstract

The direct decomposition of nitrogen oxides (NO_X) is an ideal way to remove NO_X pollution created by chemical industries and automobiles. Ba₃Y₄O₉ is a promising candidate for the NO_X direct decomposition reaction, however, its catalytic activity is not high enough and the stability is insufficient. Here, NO decomposition activity on several metal ion doped Ba₃Y₄O₉ catalysts is reported and it is found that Cu is the most effective for increasing the activity. With 10% Cu doping, the catalytic activity and the stability were improved simultaneously. Temperature programmed desorption (TPD) results indicate that doping with Cu increased the amount of surface oxygen vacancies and mobility of the lattice oxygen resulting in an increase of NO adsorption and the promotion of the decomposition of NO_X intermediate species. In situ FT-IR spectra prove that Cu doping weakened the association of NO₃⁻ species, thus promoting the decomposition of NO₃⁻ species at low temperatures, which resulted in high catalytic activity for NO_X decomposition. These results indicate that introducing Cu into the Ba₃Y₄O₉ system is an effective way to achieve high activity and a stable catalyst for the direct decomposition of NO_X.