This paper describes a study of the nature and the accessibility of the acid sites in micromesoporous mordenite zeolites obtained by desilication and dealumination and analysis of their activity and selectivity in the hydroisomerization of n-hexane. Alkaline−acid, acid−alkaline−acid, and fluorination−alkaline−acid postsynthesis treatments were employed for the preparation of micromesoporous mordenites. The FTIR spectra of adsorbed d 3 -acetonitrille, 27 Al MAS NMR, HR-TEM, and N 2 adsorption were used for quantitative analysis of the Brønsted and Lewis sites, the coordination of Al atoms, and the textural properties. The alkaline treatment causes desilication, preferably occurring along the crystal defects and resulting in the formation of a secondary mesoporous structure characterized by 5−20 nm cavities and the formation of extraframework (Al Ex ) species and terminal Si−OH groups. The Al Ex species formed by hydrolysis of perturbed or dislodged framework Al easily restrict part of the pseudomonodimensional channel structure of mordenite. The subsequent removal of Al Ex by mild acid leaching or simultaneous removal of Si and Al atoms by desilication of fluorinated zeolite result in a micromesoporous structure with a large number of unrestricted channel openings and lead to a large increase in the accessibility of OH groups for n-hexane. Thus, the sequential leaching treatments enable the formation of active acid sites in an environment of nonrestricted microporous channels with simultaneous enhancement of accessibility of the active sites and molecular transport. It is shown that the micromesoporous structure with high concentration of Brønsted sites of enhanced accessibility directs the hydroisomerization reaction toward high yields of branched isomers and shortening of the main 12-ring channels and that the larger numbers of channel openings result in an increase in selectivity, limiting nonselective subsequent cracking reactions.

The inherent properties of a single atomic carbon layer in graphene offer new opportunities for the creation of catalytically active centers tailored on a molecular level on a support with high thermal stability, as well as outstanding mechanical properties and specific surface area. We demonstrate that organization of the two-dimensional system of the carbon layer into threedimensional (3D) graphene-like catalytic materials with connectivity of a pore network providing good accessibility to the active centres allows the preparation of a conceptually new class of catalytic materials exploiting graphene properties. In this study, 3D graphene-like microporous carbons, denoted as β-graphene and Y-graphene, were synthesized by nanocasting of beta ( * BEA) and faujasite (FAU) zeolite templates. Structural analyses show that the materials are characterised by 3D assembled and highly stable single atomic graphene layers forming an open porous system resembling the regular channel system of the zeolites with a specific surface area comparable to the surface area of graphene. The materials effectively catalyse the hydrogenation of alkenes, alkynes and cycloalkenes into the corresponding alkanes and cycloalkanes. The materials facilitate catalytic intramolecular rearrangements including the selective isomerisation of double bonds and branching of linear chains, as well as stereo-selective isomerisation of unsaturated hydrocarbons.

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