Pd-Ag alloy nanoparticles were synthesized by W/O microemulsion method and then deposited on Al2O3 to form the supported catalyst by microemulsion impregnation technology.The nanoparticles of sample were characterized by UV/Vis and HRTEM.Their catalytic performances were investigated by the acetylene selectivity hydrogenation.The results indicated that uniform Pd-Ag bimetallic alloy nanoparticles with the minimum size of 1～2nm were formed in the measured area of microemulsion.The growth of nanoparticles was effectively limited by both the droplet size of microemulsion and the protection of PVP added into the system Brij30/n-octance/water.The size stability of particles was enhanced.Pd-Ag alloy nanoparticles were well dispersed on Al2O3 support with the thin PVP film form.The number of particles synthesized was the most and the particle size was the smallest when the molecular weight of PVP was 8000～10000,and cPVP8∶c(Pd+Ag) was 0.1.High acetylene conversion and selectivity to ethylene for acetylene hydrogenation was achieved on the catalyst Pd-Ag/Al2O3.
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