In order to carry out water splitting using solar energy, the materials used should absorb visible light and have appropriate conduction band levels to allow the production of H2.
Abe and coworkers have made TaON and Ta3N5 photoanodes displaying high photocurrent which represent an exciting step towards this goal.
Read the Energy and Environmental Science paper at:
Fabrication of efficient TaON and Ta3N5 photoanodes for water splitting under visible light irradiation
Masanobu Higashi, Kazunari Domen and Ryu Abe
Energy Environ. Sci., 2011