Synthesis of hydrothermally stable, hierarchically mesoporous aluminosilicate Al-SBA-1 and their catalytic properties

Synthesis, Characterization and Use of Mesoporous Silicas of the Following Types SBA-1, SBA-2, HMM-1 and HMM-2

Mesoporous silicas have enjoyed great interest among scientists practically from the moment of their discovery thanks to their unique attractive properties. Many types of mesoporous silicas have been described in literature, the most thoroughly MCM-41 and SBA-15 ones. The focus of this review are the methods of syntheses, characterization and use of mesoporous silicas from SBA (Santa Barbara Amorphous) and HMM (Hybrid Mesoporous Materials) groups. The first group is represented by (i) SBA-1 of three-dimensional cubic structure and Pm3n symmetry and (ii) SBA-2 of three-dimensional combined hexagonal and cubic structures and P63/mmc symmetry. The HMM group is represented by (i) HMM-1 of two-dimensional hexagonal structure and p6mm symmetry and (ii) HMM-2 of three-dimensional structure and P63/mmc symmetry. The paper provides comprehensive information on the above-mentioned silica materials available so far, also including the data for the silicas modified with metal ions or/and organic functional groups and examples of the materials applications.

Polyelectrolyte-Surfactant Mesomorphous Complex Templating: A Versatile Approach for Hierarchically Porous Materials

Hierarchically porous materials have attracted great attention because of their potential applications in the fields of adsorption, catalysis, and biomedical systems. The art of manipulating different templates that are used for pore construction is the key to fabricating desired hierarchically porous structures. In this feature article, the polyelectrolyte-surfactant mesomorphous complex templating (PSMCT) approach, which was first developed by our group, is elaborated on. During the organic-inorganic self-assembly, the mesomorphous complex of the polyelectrolyte and oppositely charged surfactants would undergo in situ phase separation, which is the key to fabricating hierarchically porous materials. The recent progress in the utilization of the PSMCT method for the synthesis of hierarchically porous materials with tunable morphologies, mesophases, pore structures, and compositions is reviewed. Meanwhile, the functions of the hierarchically porous materials synthesized by the PSMCT method and their applications in adsorption, catalysis, drug delivery, and nanocasting are also briefly summarized.

Dual-Purpose 3D Pillared Metal-Organic Framework with Excellent Properties for Catalysis of Oxidative Desulfurization and Energy Storage in Asymmetric Supercapacitor

This study proposes an approach for improving catalysis of oxidative desulfurization (ODS) of diesel fuel under mild reaction conditions and enhancing supercapacitor (SC) properties for storage of a high amount of charge. Our approach takes advantage of a novel dual-purpose cobalt(II)-based metal-organic framework (MOF), [Co(2-ATA)₂(4-bpdb)₄] _n (2-ATA: 2-aminoterephthalic acid and 4-bpdb: N, N-bis-pyridin-4-ylmethylene-hydrazine as the pillar spacer), which is called NH₂-TMU-53. Due to the stability of the used compound, we decided to evaluate the capability of this compound as a novel electrode material for storing energy in supercapacitors, and also to investigate its catalytic capabilities. It is demonstrated that the addition of H₂O₂ as an oxidant enhances the efficiency of sulfur removal, which indicates that NH₂-TMU-53 can efficiently catalyze the ODS reaction. According to the kinetics results, the catalyzed process follows pseudo-first-order kinetics and exhibits 15.57 kJ mol^-1 activation energy. Moreover, with respect to the radical scavenging evaluations, the process is governed by direct catalytic oxidation rather than indirect oxidative attack of radicals. Furthermore, NH₂-TMU-53 was applied as an electrode material for energy storage in SCs. This material is used in the three-electrode system and shows a specific capacitance of 325 F g^-1 at 5 A g^-1 current density. The asymmetric supercapacitor of NH₂-TMU-53//activated carbon evaluates the further electrochemical activity in real applications, delivers the high power density (2.31 kW kg^-1), high energy density (50.30 Wh kg^-1), and long cycle life after 6000 cycles (90.7%). Also, the asymmetric supercapacitor practical application was demonstrated by a glowing red light-emitting diode and driving a mini-rotating motor. These results demonstrate that the fabricated device presents a good capacity for energy storage without pyrolyzing the MOF structures. These findings can guide the development of high-performance SCs toward a new direction to improve their practical applications and motivate application of MOFs without pyrolysis or calcination.

Hierarchically Porous Silica Prepared with Anionic Polyelectrolyte-Nonionic Surfactant Mesomorphous Complex as Dynamic Template

Hierarchically porous silica KIT-6 and SBA-15 mesostructures were successfully synthesized by using a mesomorphous complex of a nonionic triblock copolymer (pluronic P123) and an anionic polyelectrolyte (polyacrylic acid) as the dynamic template. The obtained mesoporous silica materials possessed both ordered mesopores (∼7 nm) and nanopores (∼15-50 nm), and the long-range order of the mesophase was not perturbed by the embedded larger secondary nanopores. Moreover, hierarchically porous silica KIT-6 exhibited enhanced adsorption capacity in enzyme and protein immobilization, which was attributed to the hierarchically porous structure.

Bifunctional Cage-Type Cubic Mesoporous Silica SBA-1 Nanoparticles for Selective Adsorption of Dyes

Bifunctional SBA-1 mesoporous silica nanoparticles (MSNs) with carboxylic acid and amino groups (denoted as CNS-10-10) have been successfully synthesized, characterized, and employed as adsorbents for dye removal. Adsorbent CNS-10-10 shows high affinity towards cationic and anionic dyes in a wide pH range, and exhibits selective dye removal of a two-dye mixture system of cationic methylene blue and anionic eosin Y. By changing the pH of the medium, the selectivity of the adsorption behavior can be easily modulated. For comparison purposes, the counterparts, that is, pure silica SBA-1 MSNs (CS-0) and those with either carboxylic acid or amino functional groups (denoted as CS-10 and NS-10, respectively) were also prepared to evaluate their dye-adsorption behaviors. As revealed by the zeta-potential measurements, the electrostatic interaction between the adsorbent surface and the dye molecule plays an important role in the adsorption mechanism. Adsorbent CNS-10-10 can be easily regenerated and reused, and maintains its adsorption efficiency up to 80 % after four cycles.

Synthesis of a multi-branched dandelion-like SAPO-11 by an in situ inoculating seed-induced-steam-assisted conversion method (SISAC) as a highly effective hydroisomerization support

A dandelion-like SAPO-11 with multiple branches was fabricated by seed-induced-steam-assisted conversion, which combined an in situ inoculating seed method (the initial gel pre-crystallized at 433 K for 24 h) and steam-assisted conversion process.

Biomimetic synthesized bimodal nanoporous silica: Bimodal mesostructure formation and application for ibuprofen delivery

The present paper innovatively reports bimodal nanoporous silica synthesized using biomimetic method (B-BNS) with synthesized polymer (C16-L-serine) as template. Formation mechanism of B-BNS was deeply studied and exploration of its application as carrier of poorly water-soluble drug ibuprofen (IBU) was conducted. The bimodal nanopores and curved mesoscopic channels of B-BNS were achieved due to the dynamic self-assembly of C16-L-serine induced by silane coupling agent (3-aminopropyltriethoxysilane, APTES) and silica source (tetraethoxysilane, TEOS). Characterization results confirmed the successful synthesis of B-BNS, and particularly, nitrogen adsorption/desorption measurement demonstrated that B-BNS was meso-meso porous silica material. In application, B-BNS loaded IBU with high drug loading content due to its enlarged nanopores. After being loaded, IBU presented amorphous phase because nanoporous space and curved mesoscopic channels of B-BNS prevented the crystallization of IBU. In vitro release result revealed that B-BNS controlled IBU release with two release phases based on bimodal nanopores and improved dissolution in simulated gastric fluid due to crystalline conversion of IBU. It is convincible that biomimetic method provides novel theory and insight for synthesizing bimodal nanoporous silica, and unique functionalities of B-BNS as drug carrier can undoubtedly promote the application of bimodal nanoporous silica and development of pharmaceutical science.

Low temperature oxidative desulfurization with hierarchically mesoporous titaniumsilicate Ti-SBA-2 single crystals

Hierarchically porous Ti-SBA-2 with high framework Ti content (up to 5 wt%) was firstly synthesized by employing organic mesomorphous complexes of a cationic surfactant (CTAB) and an anionic polyelectrolyte (PAA) as templates. The material exhibited excellent performance in oxidative desulfurization of diesel fuel at low temperature (40 °C or 25 °C) due to the unique hierarchically porous structure and high framework Ti content.

A facile and novel approach for preparing monodispersed hollow aluminosilica microspheres with thin shell structures

Monodispersed hollow aluminosilica microspheres with thin shell structures have been successfully synthesized via a facile, novel method.