Materials issues for photoelectrochemical water splitting

PETR 26

John A. Turner, John_Turner@nrel.gov and Todd G. Deutsch, Todd_Deutsch@nrel.gov. Hydrogen Technologies & Systems Center, National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401
The direct photoelectrochemical (PEC) splitting of water is a one-step process for the production of H2 using solar irradiation; water is split directly upon illumination. This system utilizes an illuminated semiconductor material immersed in aqueous solution to decompose water directly. Light is absorbed in the semiconductor and water is split at the semiconductor surface. To date, no semiconducting material has been discovered that simultaneously meets all the criteria required for economical hydrogen production via light-driven direct water splitting. Whilst considerable work has been directed at metal oxides due to their expected stability, little thought has been given to the requirement that PEC devices must have the same fundamental internal quantum efficiency as the commercial high efficiency PV devices. This report will summarize our efforts on PEC materials and tandem cells for photoelectrochemical water splitting. Issues relating to metal oxides will also be discussed.