Synthesis and hydrogen isomerization performance of ordered mesoporous nanosheet SAPO-11 molecular sieves.

In this study, ordered mesoporous nanosheet SAPO-11 molecular sieves were synthesized using uncalcined SBA-15 molecular sieves as a Si source. The effects of different Si sources on the structure and properties of SAPO-11 molecular sieves were examined, and their growth mechanism was elucidated. An electrostatically polarized region was formed between a P123 template (triblock copolymer) contained in uncalcined SBA-15 and two-dimensional channels of SBA-15 molecular sieves. When AlO 2 − and PO 2 + species diffused into this region, its electrostatic polarization promoted the preferential growth of SAPO-11 molecular sieves along the c -axis, which contained a large number of exposed catalytically active sites with acidic properties. During the isomerization of long-chain alkanes, the synthesized sieves exhibited high isomerization activity and selectivity. When the conversion rate of n -dodecane reached 87.96%, the yield of i -dodecane was 68.08%, and the yield of multi-branched i -dodecane was 31.65%. Mechanism illustration of ordered mesoporous SAPO-11 with nanosheets morphology. [Display omitted] • Ordered mesoporous nanosheet SAPO-11 sieves are synthesized from uncalcined SBA-15. • A preferential growth mechanism of nanosheet SAPO-11 sieves is proposed. • Ordered mesoporous nanosheet SAPO-11 sieves expose more pore active sites. • Hydroisomerization of long-chain n -alkanes is investigated. [ABSTRACT FROM AUTHOR]