Chemistry Seminar with Dr. Andrew Wilson from University of Louisville at 4:00pm

Abstract: 

In addition to engineering the morphology and electronic structure of electrocatalysts, local microenvironments at the electrode-electrolyte interface can markedly affect electrochemical reactions. In this talk, I will discuss two strategies that we are investigating to control concentration gradients and the chemical species at the electrode–electrolyte interface with the goal of improving activity and selectivity in electrocatalytic reactions. First, visible light excitation of noble metal plasmonic electrodes is known to generate localized charge carriers and heat. I will show that a rise in electrode surface temperature as small as 1 K from photothermal heating can induce convection in an electrolytic solution, and more than double electrochemical reaction rates. I will highlight an example where electrode surface heating affects selectivity in electrocatalytic CO2 reduction. In a second strategy, we employ external magnetic fields to selectively control the movement of charged particles in an electrolytic solution. In the electrocatalytic reduction of CO2 in a neutral, aqueous medium, I will demonstrate that the presence of a magnetic field enhances the selectivity of CO2 reduction over solvent reduction, due to a change in the interfacial pH and pH gradient at the electrode-electrolyte interface. I will also show that reacting CO2 with ionic liquids imparts a charge onto molecular CO2 complexes, allowing control over its mass transport with magnetic fields, further improving selectivity toward the CO2 reduction reaction. Collectively, the discussed results will highlight the importance of tuning chemical microenvironments with mass transport to optimize and control the outcomes of electrocatalytic reactions.