P-GaInP2 Photoelectrode for Water Reduction Stabilized with TiO2 and MoS2 Catalyst

Wednesday, 27 May 2015: 12:00
Conference Room 4F (Hilton Chicago)
J. Gu (National Renewable Energy Lab), J. L. Young (University of Colorado Boulder), N. Neale (National Renewable Energy Lab), and J. A. Turner (National Renewable Energy Laboratory)
To achieve an efficient, low cost system for the conversion and storage of solar energy, stable light absorber and robust electrocatalyst need to be coupled into one setup. Noble metals like platinum are usually used because of their high efficiency. Identifying earth-abundant material alternatives to replace precious metal catalyst is highly desired. One of the most efficient PEC systems demonstrated to date is the III-V PEC/PV tandem concept pioneered at NREL however it suffers from inert instability under aqueous solution. Here, we report studies of a p-GaInP2 photocathode protected via an atomic layer deposition of TiO2. With an appropriate TiO2 layer thickness as well as HER catalyst (MoS2) electrodeposited to the TiO2 surface, the resulting photoelectrode mediates photo-driven H2 production with a current density of ~10 mA∙cm-2 at a potential of 0 V vs. RHE under 1 sun illumination either at neutral or acidic solution. The MoS2 modified GaInP2 also showed comparable performance as GaInP2-Pt control whereas the bare surface demonstrate only half or less photocurrent density at the same condition.