Photocatalytic activities for water decomposition of RuO2-loaded AInO2 (A=Li, Na) with d10 configuration

The photocatalytic activities for water decomposition of RuO2-loaded alkaline metal indates, AInO2 (A=Li, Na), with d10 configuration were studied. Under Hg–Xe lamp illumination, RuO2-loaded LiInO2 had little activity, but RuO2-loaded NaInO2 showed the ability to photocatalytically decompose water to hydrogen and oxygen. The photocatalytic activity strongly depended on the calcination temperature of NaInO2: with increasing calcination temperature, the activity increased, passed through a maximum, and sharply decreased. In case that a part of Na ion in NaInO2 was replaced by Li or K ion, the photocatalytic activity decreased sharply with a small amount of Li and gradually with increasing content of K. The calculation based on a plane wave density function theory (DFT) was employed to elucidate the band structure of AInO2 (A=Li, Na). The photocatalytic activities were compared with those of previously reported RuO2-loaded MIn2O4 (M=Ca, Sr), and the activity differences among them are discussed.