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

Abstract

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 AlO2− and PO2+ 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%.