Synthesis, characterization, and photoluminescence property of Nd-TUD-1.

Here, five different samples of neodymium (Nd) incorporated 3D-mesoporous siliceous materials were fabricated using a single-step hydrothermal technique. Typically, all samples were subjected to several qualitative elemental and quantitative analyses such as X-ray diffraction, N2 -adsorption/desorption, scanning electron microscopy, energy dispersive X-ray, mapping, high resolution transmission electron microscopy, diffuse reflectance ultraviolet-visible, and Raman spectroscopy. The characterization results showed that at small loading of Nd (i.e. Si/Nd < 20), only isolated centres of trivalent neodymium ions were tetrahedrally coordinated in the TUD-1 matrix. However, with increasing neodymium loading, additional nanoparticles of neodymium oxide with size 10-20 nm were embedded into silica host pores. Detailed photoluminescence (PL) analysis of all samples was carried out by recording the emission profiles at two diverse excitation wavelengths, 333 and 343 nm, to understand the effect of the Nd3+ environment on the PL emission spectra with special attention to the area between 400 and 600 nm. Most importantly, different peaks of the emission spectrum of each sample exhibited a distinct shape based on the Nd3+ environment. This performance was superior evidence that PL can be applied as a simple and efficient characterization tool to understand the nature of Nd3+ ion linkage with a silica matrix.

Silver-Doped Antimony Trioxide Nanocomposites for the Photocatalytic Reduction of Nitrobenzene.

A sol-gel technique was used to synthesize silver-doped antimony trioxide nanocomposites. Antimony trioxide and silver-doped antimony trioxide samples were characterized by multiple techniques. The TEM images reveal that antimony trioxide and silver-doped antimony trioxide nanocomposites have nanoparticle shapes. Antimony trioxide has a wide band gap that can be controlled by the doping of silver, and the content of doped silver plays a vital role controlling the band gap energy. The photocatalytic performance of antimony trioxide and silver-doped antimony trioxide nanocomposites was investigated via aniline preparation from the photocatalytic reduction of nitrobenzene. The XPS results reveal that the silver is found in the metallic silver state. Silver doping improves the photocatalytic activity of antimony trioxide for the preparation of aniline. This effect can be ascribed to the narrowing of the band gap and the elongation of the lifetime for electron-hole recombination of antimony trioxide photocatalyst by silver doping. Thus, a photocatalyst with improved photocatalytic activity, limited band gap and improved e-h recombination rate was synthesized by a facile sol-gel process method.