Integrating a silicon solar cell with a recently developed cobaltbased water-splitting catalyst (Co-Pi) yields a robust, monolithic, photo-assisted anode for the solar fuels process of water splitting to O2 at neutral pH. Deposition of the Co-Pi catalyst on the Indium Tin Oxide (ITO)-passivated p-side of a np-Si junction enables the majority of the voltage generated by the solar cell to be utilized for driving the water-splitting reaction. Operation under neutral pH conditions fosters enhanced stability of the anode as compared to operation under alkaline conditions (pH 14) for which long-term stability is much more problematic. This demonstration of a simple, robust construct for photo-assisted water splitting is an important step towards the development of inexpensive direct solar-to-fuel energy conversion technologies.

Pijpers, J. J. H., Winkler, M. T., Surendranath, Y., Buonassisi, T., & Nocera, D. G. (2011). Light-induced water oxidation at silicon electrodes functionalized with a cobalt oxygen-evolving catalyst. PNAS, 108(25), 10056–10061. doi:10.1073/pnas.1106545108