Direct Solar to Hydrogen Conversion: Low Cost Photoelectrodes

  • Authors: J. Engel, H. L. Tuller (in collaboration with D. G. Nocera)
  • Sponsorship: MIT Energy Initiative

With continuously growing energy demands, alternative emission-free solar-energy solutions become ever more attractive. However, to achieve sustainability, efficient conversion and storage of solar energy is imperative[1],[2]. Photoelectrolysis harnesses solar energy to evolve hydrogen and oxygen from water, thereby enabling energy storage via chemical means. This work investigates photoelectrodes that offer high conversion efficiency, long-term stability, and low cost. The focus is initially on semiconducting metal oxides in which the energy bands, the defect chemistry, and microstructures are tuned to optimize optical absorption, charge transport, and to reduce overpotentials. For high efficiency, transition metal-based oxidation catalysts[3] are implemented at the photoelectrode. The electro-deposition kinetics of these catalysts are also investigated to allow further insights into the catalytic mechanisms.

  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, Y. Liang, and 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. [↩]

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