Fri, Mar. 27, 2015, 2:30pm - 4:00pm
Frick Chemistry Laboratory, A-57
Host: Annabella Selloni
Electron-Hole Recombination Controlled by Doping Sites in Sr-doped NaTaO3
Photocatalytic splitting reaction of water is one of the promising processes for hydrogen fuel production. The photocatalysts La-doped NaTaO3 and Zn-doped Ga2O3 have the highest quantum efficiency for water splitting. Compatible activities have also been achieved by using NaTaO3 doped with alkaline-earth metals, Ca, Sr, and Ba. Hence, doping with heterometals is the key to producing hydrogen fuel efficiently. Our earlier studies revealed using time-resolved infrared absorption that the favorable metal doping to NaTaO3 restricted electron–hole recombination and enhanced the quantum efficiency as a result. Specific metal elements, despite being impurities in the host lattice, restrict recombination, but the mechanisms of this restriction are still unknown. In this study, we show that Sr2+ cations restricted electron–hole recombination and increased the steady-state population of photoexcited electrons by 300 times when used to simultaneously dope the A sites and B sites of perovskite-structured NaTaO3. The same element failed to restrict recombination when used to dope the A sites alone.