Electrodeposition from Water Nanodroplets
Ever since Democritus' time, the idea of a single atom (Greek 'atomos' = indivisible) has propagated throughout science. Millenia later in our lab, we regularly measure reactivity of single, isolated atoms and small clusters using attoliter (one liter divided into a billion parts... and those parts divided into a billion parts!) water droplets. Our lab has also developed a new method of synthesizing high entropy alloy nanoparticles, and we are using these techniques to design multifunctional electrocatalysts for applications to energy storage and conversion devices.
Our group has developed a new method to study the porosity within single nanoparticles. This method can also be used to explore how nanopores twist and wind within a nanoparticle, a physical property known as tortuosity.
Our lab is spearheading the understanding of electrocatalysis of high entropy alloy nanoparticles.
We have shown that one can control the stoichiometry of different metals in alloy nanoparticles using the nano-Drop Deposition method
Not all nanoparticles have electrical contact with the solution or the surface of an electrode, as demonstrated in our recent publication in ACS Applied Nano Materials.
The number of atoms in a cluster affects its size, and we are interested in how size and morphology affect electrocatalysis. The inset shows the reduction of protons on a platinum cluster adsorbed to a carbon fiber ultramicroelectrodes. The limiting current can be used to calculate the size of the clusters, which can be compared to a size estimate based on the face centered cubic lattice of platinum metal.
This figure describes a method to observe electrocatalysis of small clusters of platinum on relatively inert ultramicroelectrodes. The amplification occurs when platinum forms, which is capable of reducing water over gold and carbon.
This SEM micrograph shows the size of nanoelectrode after FIB milling.