Tip Enhanced Silver Growth on Shaped Controlled Nickel Nanocrystals

We report on the synthesis of Ni/Ag heterogeneous nanocrystals. Ag almost exclusively nucleates on the vertices of Ni nanopyramids and vertices and edges of Ni nanocubes. The synthesis is carried on using the decomposition of an organometallic Ni precursor to achieve a shape control (cubes and pyramids) followed by a nonaqueous galvanic replacement reaction of Ag(I). The colloids exhibit both plasmonic resonance and superparamagnetic behavior. Interestingly, the bimetallic nanocrystals display a magnetic moment higher than the pristine Ni nanocrystals, suggesting a specific magnetic polarization of the Ni/Ag interface or silver tips.