An Expansion of Polarization Control Using Semiconductor-Liquid Junctions

This report examines the concept of independent control over current and applied potential in electrocatalysis, as a means of improving control over product selectivity. Previous work, while permitting separate modulation of current and potentiostat bias, precluded independent control over the current flow and applied cell potential. This study seeks to resolve that limitation by exploiting the Schottky diode behavior inherent to semiconductor-electrolyte interfaces. Light is explored as a prospective second degree of freedom for controlling polarization in a suitably designed, photoelectrochemical (PEC) device, enabling the arbitrary selection of current with respect to an applied cell potential. In contrast to metal electrodes, the property of light-dependent carrier concentrations in semiconductors forms the operative means of controlling charge fluxes at some arbitrary applied potential in PEC devices featuring a semiconductor-liquid junction. This functionality enables exploration of polarization states distinct from those accessible with a dark cell, with implications for improved control over electrochemical reactions.