Activation of Water‐Splitting Photocatalysts by Loading with Ultrafine Rh–Cr Mixed‐Oxide Cocatalyst Nanoparticles

Abstract

The activity of many water‐splitting photocatalysts could be improved by the use of Rh III –Cr III mixed oxide (Rh 2− x Cr x O 3 ) particles as cocatalysts. Although further improvement of water‐splitting activity could be achieved if the size of the Rh 2− x Cr x O 3 particles was decreased further, it is difficult to load ultrafine (<2 nm) Rh 2− x Cr x O 3 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 2− x Cr x O 3 particles with a size of approximately 1.3 nm and a narrow size distribution onto a BaLa 4 Ti 4 O 15 photocatalyst. The obtained photocatalyst exhibited an apparent quantum yield of 16 %, which is the highest achieved for BaLa 4 Ti 4 O 15 to date. Thus, the developed loading technique of Rh 2− x Cr x O 3 particles is extremely effective at improving the activity of the water‐splitting photocatalyst BaLa 4 Ti 4 O 15 . This method is expected to be extended to other advanced water‐splitting photocatalysts to achieve higher quantum yields.