Department of Chemical Engineering

Metal-Oxide-Semiconductor (MOS) Photoelectrodes for Efficient Solar Water Splitting

Daniel Esposito, Postdoctoral Associate at the National Institute of Standards and Technology (NIST)

101 Goergen Hall

Solar-driven water splitting with Photoelectrochemical (PEC) cells is an attractive pathway for renewable production of hydrogen (H₂), but the efficiency and stability of semiconducting photoelectrodes must be improved. One promising approach to achieving both high efficiency and good electrochemical stability is the metal-oxide-semiconductor (MOS) photoelectrode design. This MOS architecture consists of catalytic metal structures, or collectors, deposited on an oxide-covered semiconductor. Of great importance to this design is the oxide layer, which must simultaneously protect the semiconductor from the potentially corrosive electrolyte while mediating tunneling of electrons between the semiconductor and collectors. Silicon is a commonly used photovoltaic material that is attractive for use in MOS photoelectrodes, but the performance of Si-based MOS electrodes demonstrated to date has been very poor, with efficiencies less than 1 %.