One-pot synthesis of Fe/Cu-SSZ-13 catalyst and its highly efficient performance for the selective catalytic reduction of nitrogen oxide with ammonia.

Series of Fe/Cu-SSZ-13 catalysts with different Fe loading content were synthesized by simple one-pot strategy. The obtained catalysts were subjected to selective catalytic reduction (SCR) of NO with NH and were characterized by various techniques. The results show that Fe/Cu-SSZ-13 catalyst with proper Fe content exhibits excellent catalytic activity with widest operation temperature window from 160 to 580°C, excellent hydrothermal stability as well as good resistance to sulfur poisoning when compared with Cu-SSZ-13, signifying its great potential for practical applications. Further characterizations reveal that the synthesized Fe/Cu-SSZ-13 catalysts present typical chabazite (CHA) structure with good crystallinity, while isolated Cu and monomeric Fe are revealed as the predominant copper and iron species. At low temperatures, isolated Cu species act as primary active sites for SCR reaction, while monomeric Fe species provide sufficient active sites for sustain the SCR activity at high temperature. Moreover, Fe over doping would lead to the damage of zeolite structure, destruction of isolated Cu site, as well as the formation of highly oxidizing FeO, thus causing deterioration of catalytic performances.