We are developing materials-generalizable chemical tools for controlling the facet structure, composition, and surface ligand environment of metal nanoparticles at the atomic scale. For example, particular challenges exist for bimetallic nanomaterials composed of two metals with differing reactivity. Fine control over the location and relative concentration of both metals in these materials is essential for tuning catalyst performance, but differing reactivity in the elemental (reduced) state generally correlates with dissimilar chemistry for the ionic metal precursors. Therefore, creative new approaches are needed to differentially control the relative rates of reduction of the two metal ion precursors.
Our group has also pioneered an innovative methodology for using fundamental electrochemical measurements in combination with electrochemically-driven nanoparticle growth in a well-controlled chemical environment to understand redox transformations and the evolution of materials under the complex conditions of colloidal nanoparticle synthesis. Importantly, the technique is one of the only available tools for the in situ collection of data regarding the chemical processes that drive metal nanoparticle formation. Much of the development of nanoparticle shape and surface structure occurs under kinetic control, and the untapped potential for fully harnessing reaction kinetics in nanoparticle growth is often described in analogy to the rich chemistry that results from kinetic control in organic chemistry. Just as many years of research have built up a solid foundation of fundamental reactions for the field of organic chemistry and molecular synthesis, the field of materials chemistry is still awaiting the fundamental chemical understanding required to fully enable predictable materials synthesis. Further, the ability to synthesize identical catalytic nanomaterials both in solution and directly on conductive substrates will enable us to probe differences in selectivity and activity for nanoscale materials across gas phase, liquid phase, and electrochemical reaction conditions and to gain mechanistic insight into key parameters of catalyst design for challenging chemical transformations relevant to the interconversion of electrical and chemical energy.
Halford, G. C.; Personick, M. L. “Bridging Colloidal and Electrochemical Nanoparticle Growth with In Situ Electrochemical Measurements.” Acc. Chem. Res. 2023, 56, 1228-1238. [Perspective/Review]
McDarby, S. P.; Wang, C. J.; King, M. E.; Personick, M. L. “An Integrated Electrochemistry Approach to the Design and Synthesis of Polyhedral Noble Metal Nanoparticles.” J. Am. Chem. Soc. 2020, 142, 21322-21335.
King, M. E.; Kent, I. A.; Personick, M. L. “Halide-Assisted Metal Ion Reduction: Emergent Effects of Dilute Chloride, Bromide, and Iodide in Nanoparticle Synthesis.” Nanoscale 2019, 11, 15612-15621.
King, M. E; Personick, M. L. “Iodide-Induced Differential Control of Metal Ion Reduction Rates: Synthesis of Terraced Palladium-Copper Nanoparticles with Dilute Bimetallic Surfaces.” J. Mater. Chem. A 2018, 6, 22179-22188.