Abstract: Series of highly dispersed size-controlled nano-Au/NaZSM-5 catalysts were prepared by nitromethane reduction-colloid gold immobilization method. Taking heterogeneous CO oxidation as a model reaction, the influences of Au particle size, pH value, reaction temperature, reaction time, activation temperature and Au loading amount on the activities of the catalysts were investigated. These catalysts were characterized by means of transmission electron microscopy(TEM), powder X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and H₂ temperature programmed reduction(H₂-TPR) to verify the surface chemical states and the structures of the catalysts. The results show that both the preparation procedure and the reaction conditions have great influences on the sizes of gold particles and the activities of Au/NaZSM-5 catalysts. The performances of the catalysts are obviously dependent on the sizes of gold nanoparticles.

Key words: Nano-Au/NaZSM-5 catalyst, Controlled particle diameter, CO oxidation