(Invited) A Stable Integrated Photoelectrochemical Reactor for Hydrogen Production from Water

Among the major challenges in solar water, splitting to molecular hydrogen and oxygen is making a stable and affordable system for largescale applications. In this work we present results of the design, fabrication, and testing a photoelectrochemical reactor composed of the following. 1) An integrated device to reduce the balance of the system cost. 2) A concentrated sunlight to reduce the photoabsorber cost. 3) An alkaline electrolyte to reduce catalyst cost and eliminate external thermal management needs. The system consists of an III-V-based photovoltaic cell integrated with Ni foil as catalyst for oxygen production that also protects the cell from corrosion. At low light concentration and without the use of optical lenses, the solar-to-hydrogen (STH) efficiency was found to be 18.3%, while at high light concentration (up to 207 suns) with the use of optical lenses, the STH efficiency was 13%. Catalytic tests conducted for over 100 hours at 100–200 suns showed no sign of degradation nor deviation from product stoichiometry (H 2 /O 2 =2). Further tests projected a system stability of over nine years. Figure 1