With continuously growing energy demands, new alternative energy solutions become essential. In order to achieve sustainability, efficient conversion and storage of solar energy are imperative ^{[1] [2]} .  Photoelectrolysis utilizes solar energy to evolve hydrogen and oxygen from water, thereby enabling energy storage via chemical means. This work investigates photoelectrodes, which offer high conversion efficiency, long-term, stability and low cost. The focus is initially on semiconducting metal oxides in which the energy band-, defect-, and micro-structure are tuned to optimize optical absorption, charge transport, and reduced overpotentials. For high efficiency, a cobalt-based oxidation catalyst ^[3] is implemented at the photoelectrode. The electro-deposition kinetics of this catalyst are studied as part of this project to allow further insights into the catalytic mechanism.

1. N. S. Lewis and D. G. Nocera, “Powering the planet: Chemical challenges in solar energy utilization,” Proc. Natl. Acad. Sci. U.S.A. vol. 103, pp. 15729-15735, 2006.
2. R. van de Krol and Y. Liang, J. Schoonman, “Solar hydrogen production with nanostructured metal oxides,” J. Mater. Chem. vol. 18, pp. 2311-2320, 2008.
3. M. W. Kanan and D. G. Nocera, “In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co²⁺,” Science, vol. 321, pp .1072-1075, 2008.