Electron–Hole Recombination Controlled by Metal Doping Sites in NaTaO₃ Photocatalysts

High Resolution Image Download MS PowerPoint Slide In this research, sodium tantalate (NaTaO 3 ) photocatalyst was doped with Sr 2+ cations via solid-state or hydrothermal reactions. NaTaO 3 –SrSr 1/3 Ta 2/3 O 3 solid solutions that had been doped through the solid-state reaction with a Sr-rich shell covering a Sr-poor core appeared. The lattice mismatch at the heteroepitaxial core–shell interface induced surface reconstruction with regularly separated steps. The steady-state population of electrons excited with Hg–Xe lamp irradiation increased by up to 180 times in the solid-solution photocatalysts in which A sites and B sites of the perovskite-structured lattice were doped with Sr 2+ . On the other hand, A sites were selectively doped with the same cations through the hydrothermal reaction. Surface reconstruction and an enhanced electron population were absent in the A-site-doped photocatalysts. Compatible results were obtained by doping with Ca or Ba instead of Sr. Tuning of doping sites was essential to restricting recombination in NaTaO 3 photocatalysts doped with the alkaline-earth metals.