Preparation And Catalytic Performance Of Asymmetric Bowl-shaped ZSM-5 Zeolites

Based on its outstanding thermostability,high stability,and ordered channel structure,ZSM-5 zeolites are high-profiled by the researchers in the past decade,used as catalysts and adsorbents.In those reports,ZSM-5 zeolites produced with TPA template agents had different silicon ratio between their surfaces and channels,which allowed researchers discriminately etch them with lye.Among them,ZSM-5 zeolites are etched from the channels,which have a higher silicon content.As the degree of etching grows,the channels grow to mesopores,to bowl-like structures,and to hemisphere shells as an end.This structure owns a fresh inner surface with silicon hydroxyl which can be modified by siloxane,while the outer surface remains the same.Clearly,we can modify their inner surface,and harvest asymmetric modified particles.In Chapter 2,we successfully etched lipophilic modified ZSM-5 zeolites into bowl-like structure with a series of corrected lye,and studied the effect of conditions of etching.After phenylating its inner surface,the bowl-like structure can be used as viscosity reducer of oil.In Chapter 3,gold nanoparticles were selectively grown on the inner surface of the zeolites,and their catalytic properties for hydrogenation of nitrobenzene to aniline were investigated.The result showed that the bowl-like ZSM-5 nanoparticles with a cetyl-modified outer surface and gold modified inner surface had a higher catalytic activity in the reduction of nitrobenzene in its low concentration aqueous solution.The reaction velocity of this catalyst in aqueous solution was very close to normal catalysts in organic solution,so the organic solution would be no longer necessary in this reaction.