A logical microstructure-based design methodology has been applied to design a Pt-Ni/gamma-Al2O3 catalyst for the reduction of NO with H-2. Synergy in activity and selectivity were observed. The Pt-Ni nanoparticles on the synergistic catalyst were designed and tailored to mimic the microstructure of previously prepared Pt-Rh and Pt-Co nanoparticles.