RESUMEN
Uniform hexagram-shaped alpha-Fe2O3 microcrystals with tunable morphologies were fabricated by a facile hydrothermal method followed by annealing in air. The highly anisotropic hexagram-shaped alpha-Fe2O3 particles with the higher coercivity forces and remannent magnetizations showed weak ferromagnetic behaviors at room temperature and displayed the typical shape-dependent magnetic behaviors.
RESUMEN
A new nanoreactor-type composite catalyst with Au NPs embedded into the inner wall of the mesoporous TiO2 hollow spheres resulted in an enhanced synergistic effect and superb thermal stability of highly dispersed Au NPs.
Asunto(s)
Oro/química , Nanopartículas del Metal/química , Temperatura , Titanio/química , Tamaño de la Partícula , Porosidad , Propiedades de SuperficieRESUMEN
X-shaped goethite iron oxide crystals were synthesized by a surfactant-free mild hydrothermal synthesis method with the aid of fluorine ions. The X-shaped goethite crystals could readily self-assemble into microscopic hollow spheres through an oil-water interface induced self-assembly method. X-shaped hematite crystals were obtained by phase topotactic transformation of the goethite precursors. The gas sensor properties of X-shaped hematite iron oxide were investigated, and the mechanism for excellent sensor properties was discussed.
RESUMEN
Say it with flowers: Flower-like Fe(3)O(4)@Fe(OH)(3) composite catalysts show good activity and stability in the synthesis of cyclic carbonates from epoxides and CO(2). The role of hydrogen bonding between the surface hydroxyl groups of the solid and the epoxides at the solid/liquid interface is proposed as a key factor in activating the epoxide and stabilizing the ring-opened carbonate intermediates.