Coupled Heterojunction Sn2Ta2O7@SnO2: Cooperative Promotion of Effective Electron鈥揌ole Separation and Superior Visible-light Absorption

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• 作者：Junyu Lang ; Congyan Li ; Shuwei Wang ; Juanjuan Lv ; Yiguo Su ; Xiaojing Wang ; Guangshe Li
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：July 1, 2015
• 年：2015
• 卷：7
• 期：25
• 页码：13905-13914
• 全文大小：533K
• ISSN：1944-8252

文摘

In this work, a novel heterostructure integrated by two wide-band gap semiconductors, SnO<sub>2sub> and Sn<sub>2sub>Ta<sub>2sub>O<sub>7sub>, is successfully prepared via a hydrothermal approach. Hollow Sn<sub>2sub>Ta<sub>2sub>O<sub>7sub> spheres were first formed, and small SnO<sub>2sub> particles were then well-dispersed onto the outside surface of the spheres, forming a p鈥?i>n heterostructure. This heterostructure exhibits a higher potential edge that yielded enhanced photoredox ability. Further, the heterostructure is of Z-type with a consistent internal electric field direction, which effectively separates the photogenerated electron鈥揾ole pairs. Although both component semiconductors do not absorb visible light, the resulted p鈥?i>n heterostructure is surprisingly observed to show an outstanding photocatalytic performance under visible light illumination. Such a visible light response is concluded to be the consequence of the impurity band formed by Sn<sup>2+sup> doped in SnO<sub>2sub> and Sn<sup>4+sup> in Sn<sub>2sub>Ta<sub>2sub>O<sub>7sub> via in situ redox. The existence of coupled Sn<sup>2+sup> and Sn<sup>4+sup> ions in p鈥?i>n heterostructure is responsible for the absence of defects and the regenerated catalytic activities. The findings reported here may provide an approach to fabricate the new types of photocatalysts with a synergetic promotion for visible light absorption and sustained photocatalytic activities by coupling different wide-band semiconductors.