•Flower-like boehmite was template-free synthesized from a bayerite precursor via phase transformation.•The transformation procedure of bayerite to boehmite was clarified.•Flower-like boehmite consists the nano-sheets of 1–5 nm thickness.•Flower-like alumina showed an improved catalytic cracking performance in comparison to commercial alumina.Flower-like boehmite, composed of the nanosheets with 1–5 nm thickness, was synthesized from a bayerite precursor via phase transformation in a clean way. This template-free method is featured with the advantages that the mother solution containing ethanol, water and ammonium sulfate could be recovered and reused. The transformation procedure of bayerite to boehmite was clarified, in which bayerite gradually dehydrated and evolved to boehmite from the crystal outside to the inside, with the primary crystallite size of boehmite and the coordination state of aluminum remaining almost unchanged. The corresponding flower-like γ-Al2O3 derived by calcination of flower-like boehmite exhibited not only a large specific surface area (281 m2 g−1) but also bimodal porosities with the diameter distributions centered at 5.2 nm and 18.4 nm, respectively. Possessing large pore size and open pore structures, the flower-like γ-alumina showed an improved catalytic performance in the cracking of 1,3,5-triisopropylbenzene in comparison to the commercial alumina catalysts.

PLS-4 lamellar precursors, comprised of FER layers and organic structure-directing agent of diethyldimethylammonium cations, were interlayer expanded by silylation with Me2Si(OEt)2 molecules, yielding PLS-4-sil materials with a larger porosity than directly calcined PLS-4 with the CDO topology. The silylation conditions were optimized to obtain a highly ordered interlayer-expanded structure. The silylation introduced about four additional silicon atoms per unit cell to pillar the FER layers. The silicon insertion not only widened the interlayer entrance but also endowed the inorganic zeolite with organic functionality by introducing two methyl groups per silane molecule. As an organic–inorganic hybrid material, PLS-4-sil possessed changeable pore openness and hydrophilicity/hydrophobicity after controlled removal of methyl groups by calcination. Coherently, its adsorption capacities varied with calcination temperature for the adsorption of water, n-hexane and benzene molecules.Graphical abstractHighlights► Interlayer expanded zeolites were prepared by silylation of PLS-4 lamellar precursor. ► The silylation conditions were optimized to achieve a well ordered expanded structure. ► The pore opening and hydrophilicity/hydrophobicity were controlled by calcination. ► Interlayer expanded PLS-4 exhibits unique adsorption properties.