Novel insights into the surfactant-templating process leading to the formation of tailored intracrystalline mesoporosity in USY zeolite are presented in the light of the changes in the textural, morphological, and chemical properties of this zeolite produced during its treatment in a basic solution of cetyltrimethylammonium bromide (CTAB). The inability of analogous surfactants with bulkier heads to produce mesoporosity suggests that individual CTAB molecules can actually enter the zeolite through its microporosity. Once inside, the surfactant molecules self-assemble to produce the micelles responsible for the formation of mesoporosity causing the expansion of the zeolite crystals, as evidenced by He pycnometry measurements. The analysis of ultramicrotomed samples by transmission electron microscopy evidenced the formation of uniform intracrystalline mesoporosity throughout the entire crystals. In order to investigate an alternative method, namely, the dissolution and reassembly of zeolites, this was performed in USY leading to the formation of composite materials, which are distinctly different from the zeolite with intracrystalline mesoporosity obtained by surfactant-templating. Finally, it was proved that the presence of mesoporosity in the initial zeolite is not needed for the surfactant-templating to occur. This was verified by surfactant-templating of a NaY zeolite, which does not present the large mesopores found in USY.

The development of intracrystalline mesoporosity within zeolites has been a long-standing goal in catalysis as it greatly contributes to alleviating the diffusion limitations of these widely used microporous materials. The combination of in situ synchrotron X-ray diffraction and liquid-cell transmission electron microscopy enabled the first in situ observation of the development of intracrystalline mesoporosity in zeolites and provided structural and kinetic information on the changes produced in zeolites to accommodate the mesoporosity. The interpretation of the time-resolved diffractograms together with computational simulations evidenced the formation of short-range hexagonally ordered mesoporosity within the zeolite framework, and the in situ electron microscopy studies allowed the direct observation of structural changes in the zeolite during the process. The evidence for the templating and protective role of the surfactant and the rearrangement of the zeolite crystal to accommodate intracrystalline mesoporosity opens new and exciting opportunities for the production of tailored hierarchical zeolites.

Highlights Desilication of TS-1 using NaOH gives rise to hierarchical zeolites.  Desilicated TS-1 exhibits a large BET surface area together with a well-developed mesoporosity.  Hierarchical TS-1 remains the activity of the original TS-1 for oxidation of small molecule.  Hierarchical TS-1 shows a significant improvement compared to original TS-1 for the oxidation of bulky molecules. AbstractA series of hierarchical TS-1 zeolites have been produced by desilication of the original TS-1 (4 wt.% Ti) using a chemical treatment with NaOH. Desilicated TS-1 zeolites exhibit a large BET surface area together with a well-developed mesoporosity. The hierarchical samples show good catalytic activity for the oxidation of small molecules while significantly higher activity for the oxidation of bulky molecules.

We studied the catalytic hydrogenation of CO 2 to methane using nickel-niobia composite catalysts. Catalysts containing 10-70 wt% Ni were synthesized by wet impregnation and tested for CO 2 hydrogenation in a flow reactor. 40 wt% was found to be the optimum Ni loading, which resulted in CO 2 conversion of 81% at 325 o C. We also calcined the Nb 2 O 5 support at different temperatures to study the influence of calcination temperature on the catalytic performance. 40wt% Ni loaded on Nb 2 O 5 , which was pre-treated at 700 o C gave higher methanation activity (91% conversion of CO 2). Time on stream study for 50 h showed a stable activity and selectivity; thus confirming the scope for practical application.

Supported iron oxide nanoparticles have been incorporated onto hierarchical zeolites by microwave‐assisted impregnation and mechanochemical grinding. Nanoparticle‐functionalised porous zeolites were characterised by a number of analytical techniques such as XRD, N2 physisorption, TEM, and surface acidity measurements. The catalytic activities of the synthesised nanomaterials were investigated in an alkylation reaction. The results pointed to different species with varying acidity and accessibility in the materials, which provided essentially different catalytic activities in the alkylation of toluene with benzyl chloride under microwave irradiation, selected as the test reaction.

Understanding/visualizing the established interactions between gases and adsorbents is mandatory to implement better performance materials in adsorption/separation processes. Here we report the unique behavior of a rare example of a hemilabile chiral three-dimensional metal−organic framework (MOF) with an unprecedented qtz-e-type topology, with formula Cu II 2 (S,S)hismox•5H 2 O (1) (hismox = bis[(S)-histidine]oxalyl diamide). 1 exhibits a continuous and reversible breathing behavior, based on the hemilability of carboxylate groups from L-histidine. In situ powder (PXRD) and single crystal Xray diffraction (SCXRD) using synchrotron radiation allowed us to unveil the crystal structures of four different host−guest adsorbates (Ar@1, N 2 @1, CO 2 @1, and C 3 H 6 @1), rationalize the breathing motion, and unravel the mechanisms governing the adsorption of these gases. Then this information was transferred to implement efficient separations of mixtures of industrial and environmental relevance, CO 2 /N 2 , CO 2 /CH 4 , and C 3 H 8 /C 3 H 6 , using 1 in packed columns as the stationary phase and dispersed in a mixed matrix membrane.

In this study, new active PCL (poly(ε-caprolactone)) films containing α-tocopherol (TOC) and MSU-X mesoporous silica were prepared by melt blending. The studied additives were directly incorporated into the polymer matrix or by impregnating TOC into MSU-X silica (PCL-IMP). Thermal, optical, oxygen and water barrier properties as well as oxidation onset parameters, were studied. Films containing MSU-X and/or TOC showed a significant increase in oxidative onset temperature (OOT) and oxidative induction time (OIT), improving thermal stability against materials oxidation by the addition of mesoporous silica and TOC into the polymer matrix. In addition, the effect of MSU-X addition on the migration behaviour of α-tocopherol from active films was investigated at 40 °C using 50% (v/v) ethanol as fatty food simulant, showing PCL-IMP films the lower release content and diffusion coefficient (3.5 × 10−15 cm2 s−1). Moreover, radical scavenging (DPPH and ABTS) and antibacterial activity against E. coli and S. aureus were favoured by the release of α-tocopherol in the developed films. The obtained results have demonstrated the potential of the new PCL-based active formulations for TOC controlled release in antioxidant and antibacterial food packaging applications.

The preparation of MOFs including a metal with an easily exchangeable oxidation state, while maintaining the same crystal structure and stability, is of paramount importance for myriad applications. In this work, a new synthesis method is reported that can be used to prepare Ce/Zr-MOFs (UiO-66 structure) having only Ce(III), a mixed-valence Ce(IV)/Ce(III), or only Ce(IV) cations, as desired. The materials are characterized using a large number of techniques, including X-ray absorption and X-ray photoelectron spectroscopies.