Model Pd-Au/SiO2 bimetallic catalysts were prepared via a microfabrication method and their catalytic activity for the hydrogenation of 1,3-butadiene was compared with thin film catalysts. The microfabricated catalyst consisted of Pd-Au squares with various surface compositions, approximately 4 mu m in size and separated by 4 mu m on a silica/silicon support. The main advantage of the microfabricated bimetallic catalysts is that alloy formation is guaranteed and XPS results showed that surface segregation occurred for the Au-rich compositions. The apparent activation energies of the bimetallic catalysts were lower than that of the pure Pd catalyst with a minimum occurring at similar to 65 at% Pd. The bimetallic catalysts, however, have fewer active Pd sites, hence the conversions are comparable. The microfabricated catalysts were more active than the thin film samples, because the thin film samples showed evidence of a high degree of sintering after pretreatment, unlike the microfabricated catalysts in which sintering did not occur.