RESUMO
Monodispersed, spherical gamma-Fe2O3 nanoparticles with controllable size in large-scale were prepared by thermolytic decomposition of FeCl3.6H2O in aliphatic amines. The nanoparticles gave very stable colloidal solution in organic solvents and can be easily converted to water-soluble by a very simple route. Their characterisation was based on TEM microscopy, XRD, Mössbauer, and magnetic measurements. Furthermore, a small amount of Pt can lead to the formation of anisotropic gamma-Fe2O3 nanostructures.
Assuntos
Compostos Férricos/química , Nanopartículas Metálicas/química , Nanotecnologia/métodos , Anisotropia , Química Orgânica/métodos , Coloides/química , Elétrons , Íons , Magnetismo , Microscopia Eletrônica de Transmissão , Conformação Molecular , Nanopartículas/química , Platina/química , Espectroscopia de Mossbauer , Difração de Raios XRESUMO
Monodispersed rhodium nanoparticles were synthesized through a flexible and very simple approach in a monosurfactant system by thermolysis of RhCl3, in which oleyl amine serves as capping, reducing agent, and high boiled solvent. The coated rhodium nanoparticles are monodispersed with 4 nm diameter and well characterised by TEM microscopy, UV-Vis spectroscopy, and X-ray diffraction measurements. The as prepared rhodium nanoparticles have the tendency to aggregate forming well-organized large symmetrical and spherical 3-D superstructures which generally have diameters between 40-60 nm as revealed by the characteristic TEM images. Due to the organic monolayer that encloses the nanoparticles are soluble in non-polar organic solvents.
Assuntos
Coloides/química , Cristalização/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Compostos Orgânicos/química , Ródio/química , Solventes/química , Teste de Materiais , Conformação Molecular , Nanotecnologia/métodos , Tamanho da Partícula , Solubilidade , Propriedades de SuperfícieRESUMO
A study of the catalytic conversion of N2O to N2 over a bimetallic Ag-Pd catalyst is described in this article. Several Ag-Pd catalytic systems were prepared supported on Al2O3 with different ratios and their catalytic activity for the direct decomposition of N2O and their reduction with CO was measured. Based on the experimental results, it was observed that Ag-Pd bimetallic catalyst (5-0.5%) was the most active for both nitrous oxide reduction and direct decomposition. This high activity seems to be connected with a synergistic effect between Ag and Pd.
