The Role of Surfactants in Colloidal and Electrochemical Syntheses of Palladium Tetrahexahedra

Shape-controlled noble metal nanoparticles show great promise for the development of selective catalysts. The development of robust syntheses for novel nanoparticle shapes and compositions is therefore of interest . We have developed a colloidal synthesis of monometallic palladium tetrahexahedra (THH) in a cetyltrimethylammonium bromide (CTAB) surfactant and have observed that the successful formation of THH is dependent on the type and lot number of the CTAB. Subtle differences in these surfactants lead to various effects on reaction rate, driving the formation of different kinetic products. As well as investigating these colloidal reactions via more traditional approaches such as electron microscopy, we electrochemically monitor reaction potentials in situ for the different CTAB conditions to gain a better understanding of the reaction kinetics. Additionally, we translate these colloidal syntheses for palladium THH and other shaped palladium particles of interest to electrochemical growth on a carbon electrode surface. Merging colloidal and electrochemical approaches allows us to attain a fuller understanding of the kinetics of this system and the mechanisms of formation for shaped palladium nanoparticles in general.