Activation of Water-Splitting Photocatalysts by Loading with Ultrafine Rh−Cr Mixed-Oxide Cocatalyst Nanoparticles
Wataru Kurashige, Yutaro Mori, Shuhei Ozaki, Masanobu Kawachi, Sakiat Hossain, Tokuhisa Kawawaki, Cameron J. Shearer, Akihide Iwase, Gregory F. Metha, Seiji Yamazoe, Akihiko Kudo, Yuichi Negishi
The activity of many water-splitting photocatalysts could be improved by the use of Rh(III)-Cr(III) mixed oxide (Rh2−xCrxO3) particles as cocatalysts. Although further improvement of watersplitting activity could be achieved if the size of the Rh2−xCrxO3 particles was decreased further, it is difficult to load ultrafine (<2 nm) Rh2−xCrxO3 particles onto a photocatalyst using conventional loading methods. In this study, we successfully established a new loading method and used it to load Rh2−xCrxO3 particles with a size of
approximately 1.3 nm and a narrow size distribution onto the BaLa4Ti4O15 photocatalyst. The obtained photocatalyst exhibited an apparent quantum yield of 16%, which is the highest achieved for BaLa4Ti4O15 to date. Thus, the developed loading technique of Rh2−xCrxO3 particles is extremely effective at improving the activity of the water-splitting photocatalyst BaLa4Ti4O15. This method is expected to be extended to other advanced water-splitting photocatalysts to achieve higher quantum yields.