Abstract
CMK-3 supported highly dispersed Au-Ag bimetallic nanoparticles with different Ag/Au ratios were prepared by a sequential impregnation-reduction method without the use of any polymer stabilizer. The physicochemical properties of these catalysts were characterized with XRD, ICP-OES, EDS, TEM, XAFS, XPS, STEM, and H-2-TPD. The introduction of Ag influenced the surface Ag/Au ratios, particle size, and electronic and structural properties. The relationship between the desorption amount of H-2 and the ideal atomic arrangements with different Ag/Au ratios on the (1 1 1) planes revealed that the isolated atomic sites on the surface of alloy nanoparticles significantly improved the ability of hydrogen dissociation and the catalytic activity. As a result, compared with the monometallic Au/CMK-3, the conversion of monoethanolamine catalyzed by 10Ag90Au/CMK-3 could increase by 23% and the apparent activation energy was reduced by 10.9 kJ.mol(-1).