Dr. Franz Geiger

Abstract:

Fundamental investigations of metal nanolayers and their applications for the oxygen evolution reaction (OER) and ocean wave energy harvesting are presented. First, nonlinear optical laser spectroscopy reveals the number of net-aligned interfacial water molecules and the energetics associated with flipping them as a function of experimental conditions (applied bias, ionic strength, pH). A spectroscopic nonlinear optical autocorrelator approach yields strong signals at wavelengths consistent with high-oxidation states oxo species that are invisible in cyclic voltammetry.  Implications for strategies to lower the OER's overpotential are discussed. Second, metal nanolayers are subjected to  wave action within a wave tank containing ocean water simulant. Electrical measurements using external resistors yield power curves that exceed 50 microwatts per wave event when a nanolayer deposited on a glass microscope slide is paired with a sacrificial anode. Voltages and currents are large enough to light up a blue light emitting diode with each wave event. The linear dependence of output power and wave height velocity is demonstrated. Implications for sustainable energy harvesting are discussed.