Silver nitrate in silver zeolite A: three-dimensional incommensurate guest ordering in a zeolite framework

Fabrication of "strong" columnar Cu2-xSe superstructures assisted by inorganic ligands

In this report, Cu(2-x)Se nanoplates with columnar superstructures have been synthesized via a facile, "green", phosphine-free, low-cost colloidal method. An inorganic tin(iv) selenium complex (Sn(2)Se(6))(4-) was attached on the surfaces of Cu(2-x)Se nanoplates directly during the synthesis of Cu(2-x)Se nanoplates. With the assistance of (Sn(2)Se(6))(4-) complexes, Cu(2-x)Se nanoplates showed "strong" self-assembly behavior and the stability of Cu(2-x)Se nanoplate superstructures was increased. Such columnar superstructures were still kept even if most of the coordinating organic ligands were removed by washing. The mechanism of the formation of "strong" columnar Cu(2-x)Se superstructures had been studied. We found the "strong" self-assemblies of Cu(2-x)Se nanoplates were formed only with the coexistence of oleylamine (OAM) and Sn-X in the synthesis process. The inorganic ligand not only played a key role in the construction of the "strong" columnar Cu(2-x)Se superstructure but also greatly improved their superior electrical property.

Fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity

Using the chemical reduction method, silver nanoparticles (Ag NPs) were effectively synthesized into the zeolite framework in the absence of any heat treatment. Zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. Silver ions were introduced into the porous zeolite lattice by an ion-exchange path. After the reduction process, Ag NPs formed in the zeolite framework, with a mean diameter of about 2.12–3.11 nm. The most favorable experimental condition for the synthesis of Ag/zeolite nanocomposites (NCs) is described in terms of the initial concentration of AgNO₃. The Ag/zeolite NCs were characterized by ultraviolet-visible spectroscopy, powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray fluorescence, and Fourier transform infrared. The results show that Ag NPs form a spherical shape with uniform homogeneity in the particle size. The antibacterial activity of Ag NPs in zeolites was investigated against Gram-negative bacteria (ie, Escherichia coli and Shigella dysentriae) and Gram-positive bacteria (ie, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus) by disk diffusion method using Mueller–Hinton agar at different sizes of Ag NPs. All of the synthesized Ag/zeolite NCs were found to have antibacterial activity. These results show that Ag NPs in the zeolite framework can be useful in different biological research and biomedical applications.

TEM studies of zeolites and ordered mesoporous materials

In the present manuscript we have reviewed recent results on transmission electron microscopy of beam sensitive materials such as zeolites and ordered mesoporous materials. The results of the investigation of the fine structure of different zeolite types as MFI, ITQ-7 and the presence of mixture of phases are shown. In addition, the incorporation of metals within the zeolitic framework and their different applications as precursors for metal nanowire growth are also described. The combination of HRTEM together with electron crystallography for solving new ordered mesoporous silica and associated analytical techniques shows the strength of electron microscopy for a full characterization of such materials.