Electrocatalysis
An electrocatalyst is a material which is used to catalyze an electrochemical reaction (i.e., an electron transfer oxidation or reduction reaction). Electrocatalysis is a crucial component to many different energy and industrial applications. In artificial photosynthesis (a process in which sunlight, water, and CO2 are converted to fuels or chemicals) electrocatalysts are used to improve the efficiency of the hydrogen evolution reaction, the oxygen evolution reaction, and/or CO2 reduction. In addition, electrocatalysts are used in fuel cells and metal-air batteries to catalyze the oxygen reduction reaction. Industrially, electrocatalysts are used in electrowinning (the process of extracting metals from their ores), electroplating (the process of coating a material usually with a thin layer of metal), and electrogalvanizing (a corrosion protection method usually applied to stainless steel).
The research goals of the Leonard laboratory include developing new electrocatalysts based on earth-abundant materials for all of the above applications. This encompasses investigating new material compositions as well as novel morphologies based on nanomaterials. In addition, the aim is to improve the understanding of the mechanisms of electrochemical reactions and how they are affected by electrocatalyst properties.
Photoelectrocatalysis
As with electrocatalysis, photoelectrocatalysis is used in artificial photosynthesis (or solar fuels) applications. Here a semiconducting material absorbs photons (i.e., light) and creates electron/hole pairs which can be separated to carry out electrochemical reactions. The research goals in photoelectrocatalysis are finding and developing new semiconductor materials and nanoscale morphologies to improve the efficiency of photoelectrochemical reactions related to solar fuel applications.
Energy Storage
Energy storage devices (e.g. Li-ion batteries, flow-batteries, electrochemical capacitors) are used in applications ranging from portable consumer electronics to “grid-scale” energy storage. One energy storage device of interest is the electrochemical capacitor which typically has a higher power density and a longer cycle-life than the Li-ion battery, but a lower energy density. The development of new nano-scale materials could increase the energy density of electrochemical capacitors without sacrificing power density or cycle-life, which could have impacts on all areas of energy storage including hybrid electric and plug-in electric vehicles.
Scanning Electrochemical Microscopy (SECM)
The Leonard group utilizes scanning electrochemical microscopy (SECM) in the development and characterization of electrocatalysts and photoelectrocatalysts. Using SECM, one is able to very accurately determine the kinetics of electrochemical and photoelectrochemical reactions. In addition, mechanistic information can be obtained by the investigation of reaction intermediates. SECM is also used in electrocatalyst and photoelectrocatalyst screening.
