α-Fe2O3 nanorings prepared by a microwave-assisted hydrothermal process and their sensing properties

A series of ordered mesoporous SiO2−CaO−P2O5 sol−gel glasses which are highly bioactive has been synthesized through evaporation-induced self-assembly in the presence of a nonionic triblock copolymer, EO20PO70EO20 (P123), template. By keeping constant the SiO2 + P2O5/P123 ratio, the influence of the CaO precursor, Ca(NO3)2·4H2O, on the mesostructure has been determined. After calcination at 700 °C, ordered mesoporous glasses are obtained, showing structures that evolve from 3D-cubic to 2D-hexagonal when the CaO content increases. The mesoporous glasses are highly bioactive compared with conventional ones, due to the increased textural characteristics supplied by the template. The bioactivity tests point out that the surface area, porosity, and 3D-structure become more important than chemical composition during the apatite crystallization stage in these materials, due to the very high textural parameters obtained.

Ordered Mesoporous Bioactive Glasses for Bone Tissue Regeneration

The strong metal–support interaction (SMSI) is of great importance for supported catalysts in heterogeneous catalysis. We report the first example of SMSI between Au nanoparticles (NPs) and hydroxyapatite (HAP), a nonoxide. The reversible encapsulation of Au NPs by HAP support, electron transfer, and changes in CO adsorption are identical to the classic SMSI except that the SMSI of Au/HAP occurred under oxidative condition; the opposite condition for the classical SMSI. The SMSI of Au/HAP not only enhanced the sintering resistance of Au NPs upon calcination but also improved their selectivity and reusability in liquid-phase reaction. It was found that the SMSI between Au and HAP is general and could be extended to other phosphate-supported Au systems such as Au/LaPO4. This new discovery may open a new way to design and develop highly stable supported Au catalysts with controllable activity and selectivity.

Strong Metal–Support Interactions between Gold Nanoparticles and Nonoxides

The AXO4 monazite-type compounds form an extended family that is described in this review in terms of field of stability versus composition. All the substitution possibilities on the cationic and anionic sites leading to the monazite structure are reported. The phosphate, vanadate, chromate, arseniate, sulphate and silicate families are described and the unit-cell parameters of pure compounds and solid solutions are gathered. The stability limits of the monazite-type structure are discussed versus several models generally correlated with geometric criteria. The effects of physico-chemical parameters such as pressure, temperature and irradiation on the monazite-type structure stability are also discussed. The structural relationships between the monazite structure and the related structures (zircon, anhydrite, barite, AgMnO4, scheelite and monoclinic BiPO4, CaSeO3, rhabdophane and SrNp(PO4)2) are described.

Crystal chemistry of the monazite structure

The implications of organically-modified silica-based materials in electrochemical science is reviewed along with some selected recent trends in the field of functionalized and sol–gel silica electrochemistry. These recent trends include the electro-assisted generation of organosilica films on solid electrode surfaces, the preparation and applications of sol–gel derived composite (carbon, gold, nanotubes) electrodes, the electrochemical characterisation of mass transfer reactions in porous functionalized silicas, solid-state electrochemistry and gas sensors involving sol–gel materials, imprinted functionalized silica, and the electrochemical characterisation and applications of ordered mesoporous organosilicas.

Exciting new directions in the intersection of functionalized sol–gel materials with electrochemistry

A simple hydrothermal method has been developed for the systematic synthesis of lanthanide orthophosphate crystals with different crystalline phases and morphologies. It has been shown that pure LnPO4 compounds change structure with decreasing Ln ionic radius:  i.e., the orthophosphates from Ho to Lu as well as Y exist only in the tetragonal zircon (xenotime) structure, while the orthophosphates from La to Dy exist in the hexagonal structure under hydrothermal treatment. The obtained hexagonal structured lanthanide orthophosphate LnPO4 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy) products have a wirelike morphology. In contrast, tetragonal LnPO4 (Ln = Ho, Er, Tm, Yb, Lu, Y) samples prepared under the same experimental conditions consist of nanoparticles. The obtained hexagonal LnPO4 (Ln = La → Tb) can convert to the monoclinic monazite structured products, and their morphologies remained the same after calcination at 900 °C in air (Hexagonal DyPO4 is an exceptional case, it transformed to tetragonal DyPO...

Systematic synthesis and characterization of single-crystal lanthanide orthophosphate nanowires.

Novel silicone surfactant was first used as the template to prepare mesostructured silica films with unusual lamellar structure Complex mesostructured silica films can be obtained using the mixture of silicone surfactantand cetyltrimethylammonium bromide (C 1 6 TAB: CH 3 (CH 2 ) 1 5 N + (CH 3 ) 3 Br - ) as the surfactant in conjunction with the sol-gel dip-coating process The results show that silicone surfactants favor the formation of lamellar structure Highly ordered long-range lamellar structure has the largest lattice constant known for lamellar materials to date reported Moreover, the hexagonal mesophase can be easily created in layered silica walls just by adding C 1 6 TAB in the silicone surfactant templating system The lamellar mesophase and the hexagonal mesoporosity in the walls were separately templated from silicone-based surfactant and C 1 6 TAB in the mixed surfactant templating systems, and thus hierarchically ordered silica formed The examples presented supply strong evidence that oxide mesophases are governed by supramolecular chain configuration; ie, unrestricted chain configuration (Si-O-Si chain in silicone surfactant) is responsible for the formation of the zero-curvature lamellar silica mesophase and restrictive chain configuration (C-C-C chain in C 1 6 TAB) for the high-curvature hexagonal mesophase, even their existing in a one-pot system

Continuous Formation of Supported Unusual Mesostructured Silica Films by Sol−Gel Dip Coating

The trans-oxamidato dicopper(II) "synthons", [Cu 2 (trans-L)] 2+ (L= oxen, oxpn, oxap, and oxpy) have been used as construction units when further connected by a second bridging ligand L′ (spacer) to fabricate supramolecular architectures via covalent and hydrogen bonding interactions. The structural topologies of the polymeric networks contained by these compounds depend mainly on the coordination modes of the spacers. When the spacers are 2-connectors bridging two synthons, the resulting compounds usually contain 1-D infinite chains, while 3- or 4-connector provides compounds containing 2-D extended coordination networks. The hydrogen bonds, in which the oxamidate, the spacer, and the water molecules are involved, are prevalent and the predominant intermolecular interactions. Compared with the polymeric networks constructed via covalent bonding interactions between synthons and spacers, the structural topologies of the 3-D supramolecular architectures fabricated via hydrogen bonding interactions are mor...

Supramolecular Architectures Based on trans -Oxamidato-Bridged Copper(II) Synthons and Intramolecular Synergism

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Hua-Xin Zhang

Papers

Systematic synthesis and characterization of single-crystal lanthanide orthophosphate nanowires.

Continuous Formation of Supported Unusual Mesostructured Silica Films by Sol−Gel Dip Coating

Supramolecular Architectures Based on trans -Oxamidato-Bridged Copper(II) Synthons and Intramolecular Synergism

Systematic Synthesis and Characterization of Single‐Crystal Lanthanide Orthophosphate Nanowires.

Supramolecular Architectures Based on Trans-oxamidato-Bridged Copper(II) Synthons and Intramolecular Synergism.