Chemists have been pursuing tantalum nitride as a possible photocatalyst for splitting water to release hydrogen and oxygen in a sustainable manner. The catalyst responds to irradiation by visible light at wavelengths below 590 nm. Unfortunately, it is a difficult material to crystallize and so has not yet lived up to expectations.

Kazunari Domen, University of Tokyo, Japan, and colleagues have demonstrated how the catalyst can be generated much more effectively in a crystalline form by modifying it with an alkaline metal salt. This leads to smaller crystalline particles that are six times more active in evolving oxygen from water. The improvement is thought to be due to morphological changes in the tantalum compound.

• Enhanced Water Oxidation on Ta₃N₅ Photocatalysts by Modification with Alkaline Metal Salts,
  Su Su Khine Ma, Takashi Hisatomi, Kazuhiko Maeda, Yosuke Moriya, Kazunari Domen,
  J. Am. Chem. Soc. 2012.
  DOI: 10.1021/ja3095747