The synthesis of shaped metal nanoparticles to meet the precise needs of emerging applications requires intentional synthetic design directed by fundamental chemical principles. We report an integrated electrochemistry approach to nanoparticle synthetic design that couples current-driven growth of metal nanoparticles on an electrode surfacein close analogy to standard colloidal synthesiswith electrochemical measurements of both electrochemical and colloidal nanoparticle growth. A simple chronopotentiometry method was used to translate an existing colloidal synthesis for corrugated palladium (Pd) nanoparticles to electrochemical growth on a glassy carbon electrode, with minimal modification to the growth solution. The electrochemical synthesis method was then utilized to produce large Pd icosahedra, a shape whose synthesis is challenging in a colloidal growth environment. This electrochemical synthesis for Pd icosahedra was used to develop a corresponding colloidal growth solution by tailoring a weak reducing agent to the measured potential profile of the electrochemical synthesis. Finally, measurements of colloidal syntheses were employed as guides for the directed design of electrochemical syntheses for Pd cubes and octahedra. Together, this work provides a cyclical approach to shaped nanoparticle design that allows for the optimization of nanoparticles grown via a colloidal approach with a chemical reducing agent or synthesized with an applied current on an electrode surface as well as subsequent bidirectional translation between the two methods. The enhanced chemical flexibility and direct tunability of this electrochemical method relative to combinatorial design of colloidal syntheses have the potential to accelerate the synthetic design process for noble metal nanoparticles with targeted morphologies.

Widespread implementation of polymer electrolyte fuel cells is limited by the performance of Pt catalysts because of the high cost of Pt and the propensity for catalyst surfaces to lose activity as a result of surface poisoning. AuPt core–shell particles show potential to address these issues, but offer new challenges because of the immiscibility of Au and Pt during particle growth. In this work, AuPt core–shell particles with distinct shapes are made using a one‐pot synthesis under mild reaction conditions by exploiting the difference in reduction rate between Au and Pt ions. Employing this approach results in smooth, well‐defined surfaces, rather than the more commonly observed dendritic or island‐like Pt shells that generally form when presynthesized Au cores are used to template Au‐core/Pt‐shell particle growth. By using the established mechanisms of Au nanoparticle growth, facile modification of particle shape and size is achieved with no significant change to the Pt surface. Consequently, this approach also offers a synthetic route to the preparation of more complex AuPt nanostructures, such as those with exotic shapes and high‐energy surface facets.

To enable the rational design of synthetic approaches for producing precisely defined nanomaterials, a detailed mechanistic understanding needs to be established. Colloidal approaches to nanoparticle growth have been used to produce many novel shape‐ and composition‐controlled nanoparticles with various important target applications. Concurrently, electrochemical approaches to nanoparticle synthesis have also been developed, though at present this field is less expansive than colloidal synthesis. This review covers recent progress in the synthesis of shaped metal, metal oxide, and alloyed nanoparticles via electrochemical methods that use specific control of potential or current in combination with tailoring of the chemical growth solution environment. These approaches have produced nanoparticles with compositions and architectures that were inaccessible via standard colloidal approaches. Importantly, electrochemical nanoparticle synthesis can also serve as a powerful tool for understanding fundamental mechanisms of colloidal nanoparticle growth. We highlight multiple promising opportunities in this growing research area.