Ammonia selective catalytic reduction of NO over Ce-Fe/Cu-SSZ-13 catalysts

A series of CHA-type trimetallic composite zeolites of Ce-x-Fe-y/Cu-SSZ-13 catalysts were prepared using Cu-SSZ-13, synthesized in a one-pot procedure, and subsequent ion-exchange with Fe3+ and Ce3+. The catalysts were characterized including TEM, XRD, XPS, SEM and BET. Their catalytic performances for selective catalytic reduction of NO with NH3 were investigated. The results of XRD revealed that the crystal structure of zeolite Ce-Fe/Cu-SSZ-13 is the same as Cu-SSZ-13. It is known from the results of BET and catalytic performance tests that larger specific surface areas and smaller pore size favor a catalytic reaction. Among the prepared Ce-x-Fe-y/Cu-SSZ-13 catalysts, Ce-0.017-Fe-0.017/Cu-SSZ-13 displayed the best SCR performance. The NO conversion was more than 90% between 200 and 500 degrees C. N-2 selectivity was above 98% within the wider temperature range of 150-550 degrees C. In addition, the catalyst demonstrated sulfur-water tolerance and effective resistance against high space velocity. The phenomena suggest that synergistic effects of Cu, Fe and Ce species improve the SCR performances and make the Ce-Fe/Cu-SSZ-13 catalyst a promising candidate for NH3-SCR technology.