Boosting the Alkali/Heavy Metal Poisoning Resistance for NO Removal by Using Iron-Titanium Pillared Montmorillonite...

It is still a big challge to improve the alkali and heavy metal resistance of deNO_x catalysts for selective catalytic reduction (SCR) of NO_x with NH₃. In this study, a novel catalyst developed by pillaring montmorillonite with iron and titanium (Fe-Ti-MMT) was proposed. It is quite interesting that high resistance to alkaline and heavy metals has been demonstrated by using Fe-Ti-MMT catalysts. It has been demonstrated that the specific pillaring synthesis procedure and further addition of the Ti pillared sites greatly contributed to the wide active temperature window and enhanced the resistance to alkali and heavy metal. The higher ratio of active Fe²⁺ species, more active acid sites, and enhanced ammonia adsorption indicated the remarkable activity as well as K and Pb resistance. Moreover, the K and Pb poisons would promote the generation of active adsorbed NO_x species on the Fe-Ti-MMT but induce the formation of stable inactive ones on that of Fe-MMT, which greatly tuned the reaction pathways and improved the reaction rate for Ti modified Fe pillared MMT catalysts. The strategy of incorporating Ti into the Fe pillared MMT catalysts strongly provides a novel inspiration for keeping excellent NH₃-SCR performance in the presence of alkali/heavy metal for NO_x removal.