Narrow Results

The thermal decomposition pathway and desorption of diethylamido of tetrakis(diethylamido)zirconium [TDEAZr, Zr(N(C₂H₅)₂)₄] on Si(100) were studied using temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). During TPD experiments, ethylethyleneimine (C₂H₅N=CHCH₃), diethylamine [NH(C₂H₅)₂], acetonitrile (CH₃CN), ethylene (C₂H₄) and hydrogen (H₂) desorbed as the main decomposition products of diethylamido, which was chemisorbed on Si(100) through the scission of the zirconium–diethylamido bond in TDEAZr. After TPD runs, the formation of silicon carbide and silicon nitride was observed on the surface by XPS, indicating that a complete decomposition of diethylamido proceeded. This could be a reaction pathway of C, N incorporation in the thin film growth using TDEAZr as a Zr precursor.

The decomposition of goethite and goethite/siderite concentrates into hematite with thermal modification was studied through the measurements of X-ray diffraction (XRD), scanning electronic microscope (SEM) and thermal gravimetric analysis (TGA). The experimental results showed that goethite decomposed into hematite directly at around 300°C without any intermediate phase and the decomposition of siderite completed at 500°C. Nanoscale granular structures were observed in the thermally treated products. It deserves highlighting that the decomposition processes proceeded from surfaces into bulks.

Cu nanoparticles have been synthesized by thermal decomposition of Cu-oleate complex, which was prepared by the reaction with CuCl₂ and sodium oleate in water solution. The monodispersed Cu nanoparticles were produced by controlling temperature (290°C). TEM images of the nanoparticles showed two-dimensional assembly of particles with diameter of 16.2 ± 2.9 nm, demonstrating the uniformity of these nanoparticles. EDX spectrum and XRD peaks of the nanoparticles showed the highly crystalline nature of the Cu structures. The decomposition of Cu-oleate complex was analyzed with TGA and the crystallization of Cu nanoparticles was observed with XRD.

Mn₃O₄ nanocrystals have been prepared using [bis(2-hydroxyacetophenato)manganese(II)] as precursor. Transmission electron microscopy analysis demonstrated nanocrystals Mn₃O₄ with an average diameter of about 20 nm. The structural study by X-ray diffraction indicates that these nanocrystals have pure tetragonal phase. The phase pure samples were characterized using X-ray Photoelectron Spectroscopy for Mn 2p level. The values of binding energies are consistent with the relative values reported in the literature.

Ceria (CeO₂) nanoparticles (NPs) have been produced from cerium nitrate and walnut shell as a worthless agricultural waste by a thermal decomposition method followed by open air calcination. These NPs further were characterized using powder X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy, energy dispersive X-ray spectroscope and Fourier transform infrared spectroscopy. Moreover, particle sizes can be tuned by changing cerium source/biomass ratio. To test the catalytic activity of cerium NPs as a heterogeneous catalyst, we selected three-component synthesis of 3,4-dihydroquinoxalin-2-amine. Also, the efficiency of CeO₂ NPs as a support for palladium NPs and subsequent use in aerobic oxidation of alcohols has been investigated. TEM image of a recovered catalyst indicates the formation of 12 nm sized palladium NPs within the cerium oxide NPs. The catalyst is quite effective for the oxidation of primary and secondary benzylic alcohols into their corresponding aldehydes and ketones under atmospheric pressure of air. Oxidation of secondary aliphatic alcohols is performed in oxygen atmosphere.

Nanostructured CuO has been successfully synthesized via Thermal decomposition method at 700^∘C. Prepared CuO was characterized using IR spectra, X-ray diffraction (XRD) and scanning electron microscopy (SEM). IR spectra confirm the metal–oxygen bonding in these nanoparticles. The XRD pattern confirms a single-phase crystalline nature of the nanoparticles. The synthesized CuO was demonstrated as an efficient catalyst in degradation of Rhodamine B in the presence of light through oxidation. More than 93% of the Rhodamine B dye was degraded after 150min. It was observed that photocatalytic degradation of dyes follows pseudo-first-order kinetics. A tentative mechanism has also been proposed for the photocatalytic degradation of dyes in the presence of copper oxide semiconductor.

The synthesis of two new methacrylates such as 2-[(cyclohexylideneamino)oxy]-2-oxoethyl methylacrylate (CHOEMA) and 2-[(cyclopentylideneamino)oxy]-2-oxoethyl methylacrylate (CPOEMA) are described. The monomers produced from the reaction of corresponding cyclohexanone O-(2-chloroacetyl) oxime and cyclopentanone O-(2-chloroacetyl) oxime with sodium methacrylate was polymerized in 1,4-dioxane solution at 65°C using AIBN as an initiator. The monomers and their polymers were characterized by IR, ¹H- and ¹³C-NMR spectroscopy. The glass transition temperature of the polymers was investigated by DSC and the apparent thermal decomposition activation energies (E_d) were calculated by Ozawa and multiple heating rate kinetics (MHRK) method using the Shimadzu TGA thermobalance. By using gel permeation chromatography, weight-average (M_w) and number-average (M_n) molecular weights and polydispersity indices of the polymers were determined. The antibacterial and antifungal effects of the monomers and polymers were also investigated on various bacteria and fungi. The photochemical properties of the polymers were investigated by UV and FTIR spectra.

For exploring the interesting solvent effect on structure and morphology, a variety of MgWO₄ nanoparticles were prepared by a one-pot solvothermal method with different proportional solvents of water and ethylene glycol. The results showed that monoclinic wolframite crystalline structure of MgWO₄ was successfully synthesized, corresponding to two standard cards of MgWO₄ (JCPDS No. 27-0789) and MgWO₄ (JCPDS No. 19-0776), respectively. The morphology of MgWO₄ nanoparticles presents eight different shapes and orderly transforms from one shape to another with increasing water content in mixed EG-water solvents, and a possible mechanism was proposed. The catalytic activities of these MgWO₄ nanoparticles on the thermal decomposition of Ammonium Perchlorate (AP) were compared using differential scanning calorimetry (DSC) method, and found to present good change rule with particle size.