Ultrasmall palladium nanoparticles (1.5–2.5 nm) encapsulated in metal–organic frameworks (MOFs) have been prepared by introducing a palladium precursor into a highly porous and hydrothermally stable amine-functionalized UiO-66 (NH₂-UiO-66) via a direct anionic exchange and subsequent H₂ reduction. The prepared Pd@NH₂-UiO-66 catalyst was then applied in the hydrodeoxygenation of vanillin (a typical model compound of lignin) at a low H₂ pressure in aqueous media. Excellent catalytic results (100% conversion of vanillin with exclusive selectivity for 2-methoxy-4-methylphenol) could be achieved over the developed 2.0 wt% Pd@NH₂-UiO-66 catalyst under mild conditions. Furthermore, the catalytic activity and selectivity were not affected after six reaction cycles indicating excellent stability and reproducibility of this catalyst system. It was found that the presence of free amine groups in the framework of NH₂-UiO-66 plays a key role in the formation of uniform, well-dispersed and leaching resistant palladium nanoparticles within the MOF host. Moreover, the developed Pd@NH₂-UiO-66 exhibits a novel synergetic catalysis in the hydrodeoxygenation due to the cooperation between the well-dispersed metallic Pd sites and the amine-functionalized MOF support, in which Pd offers hydrogenation activity and the MOF support facilitates hydrogenolysis of the intermediate vanillin alcohol to the 2-methoxy-4-methylphenol product.

Li₂ZrO₃ nanocrystals with improved CO₂ capture properties were synthesized by a citrate sol–gel method. The morphology and structure of the synthesized Li₂ZrO₃ samples were characterized in detail by SEM, TEM, and XRD techniques. The CO₂ capture–regeneration properties of these nanocrystals were investigated by thermogravimetric analysis (TGA) over a wide range of temperatures and of CO₂ partial pressures. The nanosized Li₂ZrO₃ crystallites with a tetragonal phase exhibit a better CO₂ capture performance than reported sorbents, exhibiting a faster uptake and a higher, nearly stoichiometric adsorption capacity (∼26 wt.%). Furthermore, the adsorbent shows a good stability, confirmed by capture–regeneration cycles. Based on these excellent properties, application in sorption-enhanced reaction process (SERP) is anticipated.

Fe-ZSM-5 zeolites with uniform crystal size and shape were synthesized by a hydrothermal method, and these parent zeolites were desilicated by an alkaline-treatment method to obtain mesoporous Fe-ZSM-5 (meso-Fe-ZSM-5) zeolites. Both Fe-ZSM-5 and meso-Fe-ZSM-5 zeolites were characterized by XRD, N₂ adsorption–desorption, ICP-AES, SEM, TEM, UV-vis, and TGA techniques and as catalysts they were used in the direct oxidation of benzene to phenol (BTOP) by N₂O as oxidant. The meso-Fe-ZSM-5 catalysts show a much higher catalytic activity and stability, compared to the parent Fe-ZSM-5 catalysts. A comparison study on the uptakes of benzene in the parent and alkali-treated zeolites indicates that the internal mass-transfer limitations of the meso-Fe-ZSM-5 zeolites are significantly improved due to the introduction of intracrystalline mesoporosity, resulting in a better catalytic activity and stability in the BTOP reaction. Desilication in the alkaline medium of Fe-ZSM-5 crystals enables a more efficient utilization of the zeolite in the BTOP reaction that is strongly affected by diffusional limitations.