Photocatalytic overall water splitting on Pt nanocluster-intercalated, restacked KCa 2 Nb 3 O 10 nanosheets: the promotional effect of co-existing ions.

Promotional effects of co-existing ions on overall water splitting into H 2 and O 2 have been studied in bulk-type semiconductor photocatalysts ( e.g. , TiO 2 ), but such an effect remains unexplored in two-dimensional nanosheet photocatalysts. Here we examined the effect of co-existing ions on the photocatalytic water splitting activity of Pt nanocluster-intercalated KCa 2 Nb 3 O 10 nanosheets. Interestingly, not only anions, as usually observed in bulk-type photocatalysts, but also cations had a significant influence on the photocatalytic performance. The rates of H 2 and O 2 evolution over Pt/KCa 2 Nb 3 O 10 as well as the product stoichiometry were improved in the presence of NaI. I - ions were found to effectively suppress undesirable backward reactions, consistent with the previous work by Abe et al. ( Chem. Phys. Lett. , 2003, 371 , 360-364). On the other hand, Na + ions in the reaction solution were exchanged for K + in the interlayer space of KCa 2 Nb 3 O 10 during the water splitting reaction, which promoted interlayer hydration and consequently improved photocatalytic performance.