Promoting Syngas to Olefins with Isolated Internal Silanols‐Enriched Al‐IDM‐1 Aluminosilicate Nanosheets

Selective conversion of syngas to value‐added olefins has attracted considerable research interest. Regulating product distribution remains challenging, such as achieving higher olefin selectivity, propylene/ethylene (P/E) and olefin/paraffin (O/P) ratios. A new pentasil zeolite Al‐IDM‐1 with recently approved −ION structure, composed of 17‐membered‐ring (MR) extra‐large lobed pores and intersected 10‐MR medium pores, shows a C2–6= selectivity up to 85 % and a high O/P value of 14 in the conversion of syngas when being combined with ZnaAlbOx oxide. Moreover, for the high‐silica Al‐IDM‐1 with Si/Al ratio of 400, the selectivity of propylene and butene accounts for 88 % in C2–4=, resulting in high P/E (>4) and butene/ethylene (B/E >3) ratios. The high C3–4= selectivity is contributed by two main reasons, that is, the relatively weak acidity of Al‐IDM‐1 zeolite enhances the olefin‐based cycle revealed by the probe reactions of methanol‐to‐propylene (MTP) and 1‐hexene cracking, and the rich isolated internal SiOH groups in Al‐IDM‐1 promote the desorption of C3–4=, once they are formed inside zeolite pores. The bifunctional catalyst composed of Zn2Al3O4 and Al‐IDM‐1 with 17‐membered‐ring pores and internal isolated silanols exhibits high propylene and butene selectivity accounting for 88 % in C2–4=. The weak acidity prohibited the second reaction of olefins and isolated internal SiOH groups and promoted the desorption of C3–4= molecules.