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Abstract: A superacid mesostructured catalyst was directly synthesized by adding sulfuric acid to mesoporous zirconia–silica synthesis mixtures, and was characterized by HRTEM, XRD, UV–Vis, nitrogen sorption, NH3–TPD, and Pyridine–FTIR. The XRD patterns and electron diffraction micrographs of the calcined samples showed the ordered mesoporous structure and tetragonal crystalline in frameworks. The ammonia TPD, pyridine in situ FTIR, and paraffin isomerization illustrated a new acidic property of the samples. The synthesis of the mesoporous materials, which have stable crystalline frameworks, high surface area, and strong acidity, is very likely to have important technological implications for catalytic reactions of large molecules. [Copyright &y& Elsevier]

[Display omitted] • Pt@SSZ-13@β with only spillover hydrogenation is designed and prepared. • Effects of hydrogenation modes on naphthalene hydrocracking are investigated. • Hydrogenation modes influence the reaction pathway of naphthalene hydrocracking. • Pt@SSZ-13@β gave higher yields to BTX than Pt/(SSZ-13@β) and (Pt/SSZ-13)@β. A Pt@SSZ-13@β core-shell catalyst is designed and successfully prepared for investigating the effects of spillover hydrogenation on hydrocracking of naphthalene. The Pt NPs encapsulated in SSZ-13 cages are inaccessible to naphthalene due to its lager size than the pore size of SSZ-13. Thus, hydrogenation functional over Pt@SSZ-13@β is mainly realized via spillover hydrogenation. Pt@SSZ-13@β exhibits higher selectivity to the desired BTX and less naphthenic products than (Pt/SSZ-13)@β and Pt/(SSZ-13@β) at above 90 % naphthalene conversion. These results indicate the hydrogenation modes resulting from the location of the supported Pt NPs in core-structure catalysts can affect the metal-acid balance, and the spillover hydrogenation can effectively suppress the deep hydrogenation of tetralin in hydrocracking of naphthalene, thereby changing the reaction path and improving the selectivity of BTX. In addition, Pt@SSZ-13@β shows a better sulfur-tolerant ability than Pt/(SSZ-13@β). This work provides a new synthetic strategy for preparing zeolite-based bifunctional catalyst. [ABSTRACT FROM AUTHOR]

A solvothermal-assisted evaporation-induced self-assembly (SA-EISA) approach has been developed for the synthesis of ordered mesoporous alumina (OMA) materials with high thermal stability and improved performance in catalysis. In conventional EISA process, the evaporation step is accompanied by the hydrolysis of organic aluminum precursors, thus the evaporation conditions have significant influences on the reaction and the final structure of OMA. In our approach, the solvothermal treatment step promotes the complete hydrolysis of aluminum precursors and produces partially condensed cluster-like aluminum hydroxyl species, which allows the formation of OMA in a broad range of evaporation conditions. Compared to mesoporous alumina obtained by conventional EISA process, OMA materials prepared by SA-EISA approach exhibit higher specific surface area, pore volume and thermal stability. When used as supporting material s for vanadium oxide catalyst, OMA materials obtained by the SA-EISA approach exhibit excellent activity, selectivity and stability for ethylbenzene dehydrogenation with carbon dioxide as a mild oxidant. Our contribution has provided new understanding in the synthesis of OMA materials with improved performance for catalytic applications. [ABSTRACT FROM AUTHOR]

Adsorption and diffusion properties of n-octane in meso-structured HZSM-5 zeolites were studied by high precision intelligent gravimetric analysis (IGA) and ZLC technology between 293 K and 393 K. As expected, great increase in adsorption capacity and diffusion efficient of n-octane in the mesostructured HZSM-5 zeolites was observed compared with conventional HZSM-5. At the same time, the adsorption activation energy of n-octane in the mesostructured HZSM-5 zeolites was significantly decreased. The adsorption heats with low n-octane loading showed a clear decline with increase of mesoporosity in the zeolite samples. These results clearly indicate that introduction of mesopores into the zeolites offered a short diffusion path and high diffusion rate for reactants and products, which resulted in a high yield of fuel oil and an enhanced resistance against the catalyst deactivation in the reaction of methanol to gasoline. [ABSTRACT FROM AUTHOR]

Abstract: Organotin compounds of (MeO)2ClSi(CH2)3SnCl3 have been grafted on a series of mesosporous silicas, as proved by XRD, N2 adsorption/desorption experiments and FTIR, diffuse reflectance UV–vis and 13C CP/MAS NMR spectroscopies. A further substitution of Cl− bonded to Sn4+ by CH3O− led to the formation of a series of active heterogeneous catalysts for the direct synthesis of dimethyl carbonate from methanol and CO2. The catalytic properties of these catalysts depended on the structure, crystal size and surface properties of mesoporous silicas. SBA-15 as a host was superior to SBA-16 and large-pore Ia3d. In addition, the methods used for removing surfactants occluded in mesoporous silicas had strong influences on the catalytic performance as a result of significantly affecting the surface areas and the concentrations of surface hydroxyl groups of the mesoporous silicas. The extraction of surfactants by an ethanol–HCl solution should be available. An increase in the reaction time, reaction temperature, methanol amount and CO2 pressure significantly increased the dimethyl carbonate yield before reaching thermodynamic equilibrium. The dimethyl carbonate yield could also be increased by adding dehydration agents to the reaction system. 2,2-Dimethoxypropane gave a much higher dimethyl carbonate yield than 3A molecular sieve and tetramethyl orthorsilicate. The prepared organotin/mesoporous silica catalysts were highly stable, as corroborated by the findings that the dimethyl carbonate yield obtained over the SBA-15-immoilized organotin compound did not decrease within six repeated runs with regeneration under the same reaction conditions and that the tetrahedral coordination state of Sn species was maintained after reaction. [Copyright &y& Elsevier]

Abstract: A series of Ru(III) tetrahydro-Schiff base complexes (denoted as Ru[H4]-Schiff base with Schiff base=salen, salpn and salcn, see ) were encapsulated in the supercages of zeolite Y by flexible ligand method. The prepared catalysts were characterized by X-ray diffraction, diffuse reflectance UV–Vis spectroscopy, Infrared spectroscopy, elemental analysis, as well as N2 adsorption techniques. It was shown that upon encapsulation in zeolite Y, Ru(III) tetrahydro-Schiff base complexes exhibited higher activity for the hydrogenation of benzene than the corresponding Ru(III)-Schiff base complexes. This indicates that hydrogenation of the C the Schiff base ligands led to a modification of the coordination environment of the central Ru(III) cations. The stability of the prepared catalysts has also been confirmed against leaching of the complex molecule from the zeolite cavities, as revealed by the result that no loss of catalytic activity was observed within three successive runs with regeneration. [Copyright &y& Elsevier]

Ir/H-SSZ-13 catalysts were used for methylcyclopentane (MCP) ring-opening (RO) reaction, and exhibit higher yields to RO products than H-ZSM-5, H-USY and Al 2 O 3 supported Ir catalysts. Ir species supported on H-SSZ-13-A (about 200 nm) exhibits higher activity than those on H-SSZ-13-B (about 8 μm) due to its more accessible acid sites. Ir/H-SSZ-13-A gives higher reactivity than Ir/Al 2 O 3 , especially in the case of low Ir loading because of the promotion of the strong acid sites located on the external surface of H-SSZ-13-A. This work demonstrates that SSZ-13 supported metal is a potential catalyst for RO reaction. [Display omitted] • Ir/H-SSZ-13 was used as catalyst for methylcyclopentane (MCP) ring-opening (RO) reaction. • Ir/H-SSZ-13 shows a higher yield to RO products than ZSM-5, USY and Al 2 O 3 supported Ir catalysts. • The acid sites on the external surface of SSZ-13 promote the activity of the supported Ir species. • This work expands the application range of SSZ-13. [ABSTRACT FROM AUTHOR]