Constructing Hierarchical Porous Nanoplate SAPO‐34 Molecular Sieves with Short b‐axis Length for Catalyzing MTO Reactions

The hierarchical porous nanoplate SAPO‐34 molecular sieves with short b ‐axis length were successfully synthesized via a two‐step hydrothermal crystallization method assisted by a concentrated gel system, incorporating polyethylene glycol (PEG) of varying molecular weights. The introduction of PEG was found to significantly influence the crystal structure, textural properties, and distribution of acid sites in the SAPO‐34 molecular sieve. During the initial crystallization stage, PEG chains in the precursor solution formed micelles that adsorbed crystal units, while tetraethylammonium (TEA) ions facilitated their directed assembly onto the crystal surface. As crystallization progressed, PEG molecules infiltrated into the crystal framework, where linear PEG chains interacted with active sites, promoting the formation of hierarchical pores. Furthermore, PEG contributed to the formation of a protective layer on the crystal surfaces, effectively limiting anisotropic growth and preventing excessive stacking of nanosheets. Compared to conventional microporous SAPO‐34, the resulting hierarchical porous nanoplate SAPO‐34 molecular sieves with short b ‐axis length demonstrated superior performance in the methanol‐to‐olefins (MTO) reaction, achieving a catalytic lifetime of 450 min and light olefin selectivity of 86.4%.