Mesoporous silica nanoparticles (MSNs) are experiencing rapid development in the biomedical field for imaging and for use in heterogeneous catalysis. Although the synthesis of MSNs with various morphologies and particle sizes has been reported, synthesis of a pore network with monodispersion control below 200 nm is still challenging. We achieved this goal using mild conditions. The reaction occurred at atmospheric pressure with a templating sol-gel technique using cetyltrimethylammonium (CTA(+)) as the templating surfactant and small organic amines (SOAs) as the mineralizing agent. Production of small pore sizes was performed for the first time, using pure and redispersible monodispersed porous nanophases with either stellate (ST) or raspberry-like (RB) channel morphologies. Tosylate (Tos(-)) counterions favored ST and bromide (Br(-)) RB morphologies at ultralow SOA concentrations. Both anions yielded a worm-like (WO) morphology at high SOA concentrations. A three-step formation mechanism based on self-assembly and ion competition at the electrical palisade of micelles is proposed. Facile recovery and redispersion using specific SOAs allowed a high yield production at the kilogram scale. This novel technique has practical applications in industry.

Nanosized Beta zeolites were postsynthetically modi-fied through the solid−gas reaction of highly dealuminated Beta zeolite with SnCl4 vapor at elevated temperatures. The incorporation mechanism of Sn ions and the physicochemical properties of resultant Sn-Beta-PS were characterized by various techniques. Its catalytic performance in Baeyer−Villiger oxidation was compared with the micrometer-sized Sn-Beta-F hydrothermally synthesized by conventional fluoride method. The Sn species were inserted into the framework via the reaction of the SnCl4 molecules with the silanols in the hydroxyl nests that were created by dealumination and thus occupied predominately the tetrahedral coordination sites. The Sn content gained by postsynthesis reached up to 6.2 wt %, corresponding to a Si/Sn ratio of ca. 35. The isolated Sn species exhibited Lewis acidity useful for the Baeyer−Villiger oxidation of ketones. Containing higher Sn contents and more importantly proposing less diffusion limitations to the substrates with a large molecular dimension, nanosized Sn-Beta-PS was superior to Sn-Beta-F in the selective oxidation of 2-adamantanone with hydrogen peroxide.

Recently, metal nanoclusters (MNCs) emerged as a new class of luminescent materials and have attracted tremendous interest in the area of luminescence-related applications due to their excellent luminous properties (good photostability, large Stokes shift) and inherent good biocompatibility. However, the origin of photoluminescence (PL) of MNCs is still not fully understood, which has limited their practical application. In this mini-review, focusing on the origin of the photoemission emission of MNCs, we simply review the evolution of luminescent mechanism models of MNCs, from the pure metal-centered quantum confinement mechanics to ligand-centered p band intermediate state (PBIS) model via a transitional ligand-to-metal charge transfer (LMCT or LMMCT) mechanism as a compromise model.

Germanosilicates, an important family of zeolites with increasing number of members and attractive porosities, but containing a large quantity of unstable Ge atoms in the framework, meet with great obstacles in terms of limited thermal and hydrothermal stability when it comes to practical use. A facile stabilization method thus has been developed to substitute isomorphously Ge atoms for Si atoms, giving rise to ultrastable siliceous analogues of the pristine germanosilicates.

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The conversion of the alkali‐treated intergrowth germanosilicate CIT‐13 into the single‐crystalline high‐silica ECNU‐21 (named after East China Normal University) zeolite, with a novel topology and a highly crystalline zeolite framework, has been realized through a creative top‐down strategy involving a mild alkaline‐induced multistep process consisting of structural degradation and reconstruction. Instead of acid treatment, hydrolysis in aqueous ammonia solution not only readily cleaved the chemically weak Ge(Si)−O−Ge bonds located within the interlayer double four ring (D4R) units of CIT‐13, but also cleaved the metastable Si−O−Si bonds therein. This led to extensive removal of the D4R units, and also generated silanol groups on adjacent silica‐rich layers, which then condensed to form a novel daughter structure upon calcination. Individual oxygen bridges in the reassembled ECNU‐21 replaced the germanium‐rich D4R units in CIT‐13, thereby eliminating the original intergrowth phenomenon along the b axis. With an ordered crystalline structure of 10‐ring (R) channels as well as suitable germanium‐related Lewis acid sites, ECNU‐21 serves as a stable solid Lewis acid catalyst for the shape‐selective hydration of ethylene oxide (EO) to ethylene glycol (EG) at greatly reduced H2O/EO ratios and reaction temperature in comparison with the noncatalytic industrial process.

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All-silica beta zeolite, synthesized by conventional hydroxide route, usually possesses small crystal size of a few hundred nanometers but poor hydrophobicity, whereas the fluoride-mediated one exhibits to be highly hydrophobic but microsized. To obtain nanosized all-silica beta zeolite with excellent hydrophobicity, an innovative and efficient hydrothermal route via interzeolite transformation for synthesizing all-silica beta zeolite is proposed in present study. With the assistance of beta seeds and tetraethylammonium hydroxide as the structure-directing agent, siliceous beta zeolite is well-crystallized at a high solid yield via dissolution-recrystallization of all-silica ITQ-1 crystals at an extremely low water content (HO/SiO molar ratio of 1). The obtained all-silica beta crystals are composed of 30-70 nm nanoparticles and highly hydrophobic just next to siliceous beta-F zeolite synthesized by environmentally unfriendly fluoride route, which is derived from relatively small amounts of internal defect sites. Thus, this beta zeolite is superior to other pure silica beta zeolites in the adsorption of large-sized volatile organic compounds (VOCs), which is mainly attributed to its high total pore volume and specific surface area as well as excellent hydrophobicity.