Reverse Microemulsion Synthesis And Characterization Of The Nanocatalysts

Catalytic combustion is an environmentally friendly technology, which caneffectively reduce the emissions of CO and NOx. However, synthesis of the catalystswith excellent thermal stability and high activity is a challenge to the development ofthe technology.In this paper, the nanotructured hexaaluminate catalysts were synthesized by thereverse microemulsion method, using the nontoxic and inexpensive inorganic salts,instead of the alkoxides, as reactants. The samples were characterized byN₂-adsorption, transmission electron microscopy (TEM), TGA-DTA, and X-raypowder diffraction (XRD). Therefore, the preparation is environmental-friendly andlow-cost. The study shows that the catalyst morphology could be controlledeffectively by the microemulsion microstructure; the homogeneityof precursor couldbe enhanced greatly by the reverse microemulsion method and the supercriticaldrying method; the catalyst morphology has a significant influence on its activity.Compared with the spherical particles, the one-dimmensional nanorod has higherabilityresistant to sintering.In addition, the monodispersed CdS-SiO₂ core-shell particles and hollow silicaranging from nanometers (30¹00nm) to micrometers (1.5²Î¼) were prepared byreverse microemulsions. The particles were characterized by Selected area electrondiffraction(SAED), Scanning electron microscope (SEM), X-ray fluroscence (XRF),etc. The study shows that the core size and shell thickness could be tuned simply bycontrolling the addition amount and the addition way of the reactants.