| 초록 |
Different ZSM-5 particles (both of Si/Al ∼30) were synthesized by using TBPOH with composition variation of ethanol & water. The resulting ZSM-5 particles were composed of very thin lamellae or pillars in the shape of hierarchical structure; (1) H_30; ~6 nm thick with high mesoporous ZSM-5 and (2) L_30; ~13 nm thick with low mesoporous ZSM-5. H_30 not only contained a large amount of external Brønsted acid sites (B-sites), but also had internal B-sites similar to those in the commercial ZSM-5 (Si/Al ~75) (C_75). The MTH reaction performance demonstrates that H_30 preferred to produce propene to ethene (~9.1) compared to C_75. Moreover, H_30 markedly disfavored the aromatic dealkylation process that is known to cause ethene. Contrastively, L_30, because of lower amounts of internal B-sites, showed inferior MTH performance. Furthermore, ceria-doping on H_30 enhanced the stability and improved a propene to ethene ratio (~15.0) through the passivation effect to the external B-sites. |
