One-step synthesis of high-amount Fe-doped hollow MFI zeolite by Kirkendall effect in the presence of organic acid anions

Abstract

Abstract Development of economical routes for synthesis of hollow zeolites with high amount of framework iron and high effectiveness factor is of great importance. Here, we provide a one-step and free-mesoporogen strategy to synthesize high-amount Fe-doped hollow silicate-1 with various cheap organic acids or derivative salts of organic acids. The contents of iron in zeolite and zeolite framework are ca. 3.3 wt% and 2.7 wt%, respectively. The hollow structures with the surface rich in iron have also been demonstrated. The presence of organic acid anions and the content of iron salts play the vital roles in the formation of hollow structure. In addition, the evolution process of Fe-doped hollow zeolite has been also investigated. The proposed mechanism based on the Kirkendall effect involves that high-amount iron-containing zeolite nanoparticles migrate outward relative to the nanoparticles interacted with carboxylate anions and carboxylate anions. The strategy can be successfully extended to TS-1 and ZSM-5. The high-amount Fe-doped hollow silicate-1 with high effectiveness factor exhibits an excellent catalytic performance for degradation reaction at mild conditions.