KTaO3光催化剂中锶离子控制的电子数量和水分解活性,The Journal of Physical Chemistry C

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KTaO3光催化剂中锶离子控制的电子数量和水分解活性
The Journal of Physical Chemistry C ( IF 3.3 ) Pub Date : 2019-07-18 , DOI: 10.1021/acs.jpcc.9b03640
Hanggara Sudrajat ₁ , Dikshya Dhakal ₂ , Mitsunori Kitta ₃ , Takuro Sasaki ₄ , Akiyo Ozawa , Sandhya Babel ₂ , Tomoko Yoshida , Nobuyuki Ichikuni ₄ , Hiroshi Onishi ₁

Affiliation

钾₃掺有Sr阳离子，并研究了其对整个水分解的光催化活性。通过掺杂Sr，在Sr贫乏的核上形成了富Sr的壳。扩展的X射线吸收精细结构光谱显示，Sr阳离子同时占据了K位和Ta位。建议在掺入Sr后产生占据Ta位的Sr阳离子的浓度梯度，同时Sr阳离子的浓度梯度引起导带边缘底部的能量梯度。因此，光激发电子从表面上存在的互补空穴中分离出来，这些电子通过能量梯度被驱散到主体。Sr阳离子浓度越高，产生的能量梯度越高。因此，随着Sr阳离子浓度的增加，电子-空穴的分离得到改善，电子的数量也随之增加。然而，Sr阳离子浓度的增加导致水分解活性的降低。裸露的KTaO观察到最高的水分解活性₃。提出的降低的水分解活性主要是由于富Sr壳对电子转移至助催化剂的阻碍以及富Sr壳的O ₂析出能力差。

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Electron Population and Water Splitting Activity Controlled by Strontium Cations Doped in KTaO3 Photocatalysts

KTaO₃ was doped with Sr cations, and its photocatalytic activity for the overall water splitting was investigated. By doping with Sr, a Sr-rich shell was formed over a Sr-poor core. Extended X-ray absorption fine structure spectroscopy revealed the simultaneous occupation of the K sites and Ta sites by Sr cations. A concentration gradient of Sr cations occupying the Ta sites was suggested to be produced after doping with Sr. The concentration gradient of Sr cations simultaneously induced an energy gradient of the conduction band edge bottom. Hence, photoexcited electrons are separated, which are driven away to the bulk by the energy gradient, from the complementary holes present on the surface. The higher the Sr cation concentration, the higher the energy gradient produced. Thus, the electron-hole separation is improved and the electron population accordingly increases with the increase in the Sr cation concentration. Nevertheless, the increase in the Sr cation concentration led to the decrease in the water splitting activity. The highest water splitting activity was observed for bare KTaO₃. The decreased water splitting activity was proposed to be primarily due to the blockage of the electron transfer to the cocatalysts by the Sr-rich shell and the poor O₂ evolution ability of the Sr-rich shell.

更新日期：2019-07-18

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