Cu and Ni were encapsulated into Silicalite-1(S-1)molecular sieve with different particle sizes by dissolvation-recrystallization method,based on which the hollow encapsulated catalysts with different metal doping amounts were prepared.The catalysts were characterized by X-ray powder diffraction(XRD),scanning electron microscopy(SEM),and X-ray photoelectron spectroscopy(XPS).The fixed bed reactor was used to simulate the removal of nitrogen oxides(NOx)in flue gas(n(CO)/n(NO)=13/3)from fluid catalytic cracking regeneration process under operating conditions.The results show that under the conditions of catalyst dosage 0.15 g,pressure 0.1 MPa,temperature 680 ℃ and space velocity 60000 mL/(g·h),the denitration efficiency of 3％Cu@S-1-380 is only 63％,and that of 2％Cu-0.5％Ni@S-1-380 is 100％.The formation of CuxNiy O eutectic between Ni and Cu promotes the rapid cycling between Cu+and Cu2+,and increases the redox reaction rate.The hollow cavity structure of catalyst effectively prevents metal loss and sintering,greatly improving the diffusion performance of reactants and the catalytic activity of catalyst.Under the same reaction conditions,as the particle size of molecular sieve decreases and the metal content increases,the denitrification efficiency of catalyst increases.The bimetallic co-encapsulation can significantly improve the catalytic activity.
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