Overall Water Splitting Under Visible Light Irradiation Over Ir and A-Codoped KTaO3 (A=Ca, Sr, Ba, La) Photocatalysts

Metal oxides are an attractive material group as photocatalysts, while the number of visible-light-responsive metal oxide photocatalysts especially for overall water splitting is quite limited. Herein, overall water splitting under visible light irradiation over Ir and A-codoped KTaO3 (A = Ca, Sr, Ba, La) photocatalysts is demonstrated. The Ir and A-codoped KTaO3 works by the electron transition from impurity levels formed by Ir3+ to the conduction band formed by Ta5d orbitals. The codoping of Ca, Sr, Ba, and La contributes to the formation of fine photocatalyst particles and stabilization of doped Ir as trivalent. An Rh-core/Cr2O3-shell cocatalyst loaded by photodeposition is effective for overall water splitting over Ir and La-codoped KTaO3 compared to a RhCrO3 cocatalyst loaded by impregnation and other metal-core/Cr2O3-shell cocatalysts. The Rh/Cr2O3-loaded KTaO3 codoped with Ir and La is also active for solar water splitting.

Automated summary

Metal oxides are attractive photocatalysts for water splitting, but there is a lack of visible-light-responsive metal oxide photocatalysts. In this study, the researchers demonstrated overall water splitting under visible light irradiation using Ir and A-codoped KTaO3 photocatalysts. The codoping of Ca, Sr, Ba, and La contributes to the formation of fine photocatalyst particles and stabilization of doped Ir as trivalent. The Rh-core/Cr2O3-shell cocatalyst loaded by photodeposition is effective for overall water splitting over Ir and La-codoped KTaO3. Rh/Cr2O3-loaded KTaO3 codoped with Ir and La also shows activity for solar water splitting.