An Integrated Electrochemistry Approach to the Design and Synthesis of Polyhedral Noble Metal Nanoparticles

Abstract

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.

State of the Art on Toxicological Mechanisms of Metal and Metal Oxide Nanoparticles and Strategies to Reduce Toxicological Risks

“…In the electrochemical synthesis method, it is necessary to use a bulk solution containing metal salts. This technique consists of the electrodeposition of the metal NPs in the substrate surface [ 31 , 32 ]. The main parameters to control in the process are the electrode potential and current density, which will affect the deposition kinetics as well as the nucleation and crystal growth.…”

Metal Nanoparticles and Carbon-Based Nanomaterials for Improved Performances of Electrochemical (Bio)Sensors with Biomedical Applications

“…In the recent years, the electrochemical methods became a powerful tool for NPs synthesis due to their advantages: Facile, cost-effective, quick, highly efficient and environmental friendliness leading to NPs with high purity, controlled size, shape and composition (multimetallic NPs have been electrodeposited) by adjusting some parameters (potential, time, current density, number of scans, etc.) [ 26 , 27 , 28 , 29 ].…”

Potential‐Controlled (R)Evolution: Electrochemical Synthesis of Nanoparticles with Well‐Defined Shapes

“…More recent examples have also substituted deep eutectic solvents, which are conductive ionic liquids [32] . While these classic electrolytes are often used, the common solutions employed in colloidal nanoparticle growth reactions – aqueous solutions of surfactants such as cetyltrimethylammonium chloride or bromide (CTAC or CTAB) [24,33] and even ion‐depleted solutions like water [34] – are also able to produce shaped particles under electrochemical growth conditions if there is a reasonable overall concentration of other ionic components in solution, such as the electroactive metal and halide ions.…”

“…However, a number of key advances have been made in the past 25 years which have accelerated the development of this approach and have expanded the scope of its utility and success. Reported methodologies for electrochemically synthesizing shaped nanoparticles have taken several forms including applying a constant potential or current over a set period of time; [23–24] programming multi‐step profiles which integrate oxidative cleaning steps and/or seed nucleation steps; [25–26] or introducing more complicated profiles such as square waves and cyclic potential scans [27–29] . While the various approaches may employ different strategies, in each case electrochemistry is used to control the reduction of metal ions in solution in a manner which will produce particles with specific geometric shapes and facets, most commonly on the surface of the electrode.…”