In order to prepare a highly active catalyst for the catalytic cracking of larger molecules, a novel micro-mesoporous silicoaluminophosphate composite (define as mesoporous SAPO-5) with hierarchical tri-modal pore size distributions has been firstly synthesized via post-synthetic method in acidic condition and subsequently characterized. Morphology control of the composite is attempted by adjusting pH value of the synthetic system. Three different morphologies of composite, including sphere-, rod- and net-like, are obtained in the different conditions. Possible mechanism for the formation of mesoporous SAPO-5 has been proposed. The mesoporous SAPO-5 exhibits higher cracking activity than conventional microporous SAPO-5 for cracking of 1, 3, 5-triisopropylbenzene (1, 3, 5-TIPB) under the same reaction conditions. The result indicates that the mesoporous SAPO-5 with hierarchical pore structure is favorable for catalytic cracking of large molecule. When the cumene as the reaction molecule, the microporous SAPO-5 catalyst exhibits higher conversion in catalytic cracking of cumene compared to the mesoporous SAPO-5, and the result may be attributed to that microporous SAPO-5 has much stronger acidity and specific selectivity than mesoporous SAPO-5 catalyst in catalytic cracking of cumene. Meanwhile, corresponding carbenium ion mechanism can account for the products formed during the whole reaction process.

An easy method is described for fabricating carbon sheets with nanostructures using sucrose as a carbon precursor and a layered superabsorbent polymer (LSAP) as a structure-directing agent. The method is based on the interaction of the three-dimensional polymer networks of the LSAP with a sucrose solution in the hydrogel cells. The synthesis scheme consists of: (a) preparation of the LSAP, (b) preparation of layered hydrogels by immersing the LSAP in the sucrose solution for 2 days, (c) carbonization of the layered hydrogels containing the sucrose solution. The synthesized carbon sheets show different microstructures including petal-like, regular and interleaved types, which can be controlled by simply adjusting the initial concentration of the sucrose solution in the hydrogel cells. Moreover, a formation mechanism for the carbon sheets is proposed.Graphical abstractAn easy method is described for fabricating carbon sheets with nanostructures using sucrose as a carbon precursor and a layered superabsorbent polymer as a template. These carbon sheets show different microstructures including petal-like, regular and interleaved types, which can be controlled by simply adjusting the concentration of the sucrose solution.Research highlights► An easy method is described for fabricating carbon sheets with nanostructures. ► A layered superabsorbent polymer was used as a template. ► These carbon sheets include petal-like, regular and interleaved types.

Macroporous silica–alumina composites with continuous micrometer-scale pores were synthesized by seed-induced vapor-phase transport treatment. The parent silica–alumina monolith was employed as the silica and alumina source as well as the template for the three-dimensional interconnected structure. The silicalite-1 precursor solution with dispersed zeolite seeds was drawn into the pore channels of the parent monolith for modification by in-situ and layer-by-layer methods before the hydrothermal crystallization, which was believed to play a significant inducing role in the zeolite growing process. The composites synthesized are expected to display high catalytic performance on the bulky molecules since they incorporate the strong acidic advantages of the microporous zeolite and the macroporous pathways of the monolithic skeletons for mass transport.

Novel hierarchical zeolites with continuous micrometer-scale macropores and mesopores other than popular nanometer-scale mesopores and micropores were synthesized by transforming the skeletons of the silica monolith into zeolites through both the steam-assisted conversion and nanocasting methods. Results showed the novel hierarchical zeolites exhibited high catalytic activity for catalytic cracking large molecules.

A hierarchical zeolite catalyst was synthesized by transforming the skeletons of a bimodal pore silica gel into a zeolite through a steam-assisted conversion method, and shows high catalytic activity and a long catalyst lifetime for catalytic cracking of large molecules.