Effect of Etching on Electron–Hole Recombination in Sr-Doped NaTaO3 Photocatalysts

详细信息    查看全文

• 作者：Longjie An ; Yohan Park ; Youngku Sohn ; Hiroshi Onishi
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：December 24, 2015
• 年：2015
• 卷：119
• 期：51
• 页码：28440-28447
• 全文大小：478K
• ISSN：1932-7455

文摘

Sodium tantalate (NaTaO₃) photocatalysts doped with Sr²⁺ produce core–shell-structured NaTaO₃–SrSr_1/3Ta_2/3O₃ solid solutions able to split water efficiently, when prepared via the solid-state method. In this study, the photocatalysts were chemically etched to examine the different roles of the core and shell with respect to the recombination of electrons and holes. Under excitation by Hg–Xe lamp irradiation, the steady-state population of electrons in the core–shell-structured photocatalyst with a bulk Sr concentration of 5 mol % increased by 130 times relative to that of the undoped photocatalyst. During etching for the first 10 min, the shell detached from the top of the core, and the electron population in the uncovered core further increased by 40%. This population enhancement indicates that electrons are excited in the core and recombined in the shell. Etching up to 480 min resulted in the reduction of the electron population. To interpret the population reduction in this stage of etching, a Sr concentration gradient that controls the electron population in the core is proposed.