Activation of Water-Splitting Photocatalysts by Loading with Ultrafine Rh-Cr Mixed-Oxide Cocatalyst Nanoparticles.

The activity of many water-splitting photocatalysts could be improved by the use of Rh -Cr mixed oxide (Rh Cr O ) particles as cocatalysts. Although further improvement of water-splitting activity could be achieved if the size of the Rh Cr O particles was decreased further, it is difficult to load ultrafine (<2 nm) Rh Cr O particles onto a photocatalyst by using conventional loading methods. In this study, a new loading method was successfully established and was used to load Rh Cr O particles with a size of approximately 1.3 nm and a narrow size distribution onto a BaLa Ti O photocatalyst. The obtained photocatalyst exhibited an apparent quantum yield of 16 %, which is the highest achieved for BaLa Ti O to date. Thus, the developed loading technique of Rh Cr O particles is extremely effective at improving the activity of the water-splitting photocatalyst BaLa Ti O . This method is expected to be extended to other advanced water-splitting photocatalysts to achieve higher quantum yields.