Hydrogenation of propyne verifying the harmony in surface and bulk compositions for Fe-Ni alloy nanoparticles

We investigated the catalytic properties of Fe_1-xNi_x nanoparticles prepared by a polyol-based method that allowed the precise control of their composition and structure. In the hydrogenation of propyne, the reaction rate decreased with decreasing x, which was in good agreement with the scenario that inactive Fe atoms dilute active Ni ensembles in particles at 0.55 ≤ x ≤ 1. For particles with x ≤ 0.46, it was suggested that slightly active Fe-Ni ensembles mainly contributed to the activity due to small population of active Ni ensembles. Since the change in catalytic properties with x was well explained by the assumption that the surface composition corresponded to x, it was concluded that the surface composition dominating the catalytic properties can be tuned by adjusting the entire composition of nanoparticles.