Ordered, Highly Zeolitized Mesoporous Aluminosilicates Produced by a Gradient Acidic Assembly Growth Strategy in a Mixed Template System

Abstract

Tremendous efforts have been made in recent years to synthesize ordered mesoporous zeolite materials due to the accelerating demands of industrial bulky molecule conversion. Here, we develop a novel gradient acidic assembly growth strategy to prepare ordered highly-zeolitized mesoporous aluminosilicate (SBA-16) materials in a mixed template system. This gradient acidic assembly growth strategy can achieve the high zeolitization of mesoporous aluminosilicate walls without any ordering loss of the mesostructure. The resultant highly-zeolitized mesoporous materials, composed of the intergrown zeolite sub-crystal particles (2-3 nm), exhibit high surface area (∼834 m 2 g -1 ) and pore volume (∼0.64 cm 3 g -1 ), typical channel of MFI framework (0.52 nm) and uniform mesopore (∼5.75 nm), respectively. Moreover, these highly-ordered crystallized mesostructures endow them with high exposed active sites and excellent hydrothermal stability, which consequently make their catalytic activities in bulky molecule transformations at least 10 times higher than conventional zeolites or amorphous mesoporous materials. Without the use of any special surfactants, this general synthetic process provides a brand new view for the synthesis and application of highly-crystalline ordered mesoporous materials.

Protective dissolution: generating secondary pores in zeolite by mechanochemical reaction

“…The rst hysteresis loop is attributed to the presence of internal structural defects 29 and the second to the presence of inter-crystal mesopores. 30 The hysteresis loops at low pressure zone slightly increase aer post-treatment, indicating the increase of internal structural defects. On the other hand, the hysteresis loops at high pressure zone rst increase aer mechanical grinding and heating for 1 h, but then decrease with further heating, which may be caused by the merging of mesopores into macropore.…”

Catalytic nanosponges of acidic aluminosilicates for plastic degradation and CO2 to fuel conversion

“…To further confirm the presence of strong acidity of AAS, Friedel−Crafts alkylation of anisole by benzyl alcohol, which also requires a strong acidic site and mesoporosity 38 is carried out (Fig. 3 ).…”

“…3 ). The best known zeolitized mesoporous aluminosilicates achieved ~50% conversions in 1 h under microwave irradiation at 160 °C using 100 mg of catalyst 38 . Notably, all the five AAS AC series catalysts show 100% conversion in only 15 min using 25 mg of catalyst (Supplementary Table 2 ).…”

Sheet-like silicalite-1 single crystals with embedded macropores displaying superior catalytic performance

“…[2][3][4] Diffusional transport constraints can be overcome by introducing meso-and macro-porosity into the zeolite crystals either during or after their synthesis, and various methods have been considered for introducing meso-and macro-porosity into zeolites. 2,[5][6][7] These include post-synthetic desilication/ dealumination, 8,9 as well as the nano-sized crystals assembly synthetic method, 10,11 and the hard/soft-template method via the hydrothermal or dry-gel conversion (DGC) strategy. 12,13 Of particular note is the DGC synthetic method which enables the synthesis of zeolites with hierarchical structures.…”