Boosting Photocatalytic Water Splitting by Tuning Built-in Electric Field at Phase Junction
Boosting Photocatalytic Water Splitting by Tuning Built-in Electric Field at Phase Junction
复制标题
通过调节相连接处的内置电场促进光催化水分解
DOI：
10.1039/c8ta08199a
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发表时间：
2019
影响因子：
11.9
通讯作者：
Can Li
中科院分区：
文献类型：
--
作者：
Jing Zhang;Xuebing Chen;Yu Bai;Chun Li;Ying Gao;Rengui Li;Can Li
在半导体界面构建内建电场已被证明可为光催化中的空间电荷分离提供驱动力。尽管相结（同一半导体的两种晶相之间形成的界面）已被证明在空间电荷分离方面是有效的，但通过精确调节内建电场来调控光催化活性尚未被充分理解。在这项工作中，以锐钛矿/金红石TiO₂相结为例，通过在金红石TiO₂表面制备可控的锐钛矿纳米粒子来调节相结区域的内建电场，从而控制锐钛矿相和金红石相之间的界面接触面积。我们发现光催化产氢强烈依赖于锐钛矿和金红石TiO₂之间的界面接触面积。锐钛矿/金红石相结界面接触面积与特定光催化活性之间的关系呈现出典型的火山曲线，即增加界面接触面积会增强空间电荷分离的驱动力，使更多的电子和空穴迁移到表面并参与氧化还原反应，但进一步增加界面接触面积会导致光催化活性下降。优化的界面接触是内建电场强度与光生载流子转移距离之间的最佳平衡，有利于相结区域光生电子和空穴的分离和转移。我们的工作为在半导体基光催化剂表面构建内建电场以促进太阳能转换系统中的空间电荷分离提供了新的见解。
Constructing a built-in electric field at the interface of semiconductors has been demonstrated to provide the driving force for spatial charge separation in photocatalysis. Although phase junctions (interfaces formed between two crystalline phases of the same semiconductor) have been demonstrated to be effective in spatial charge separation, regulation of the photocatalytic activity by precisely tuning the built-in electric fields is not yet well understood. In this work, taking anatase/rutile TiO2 phase junction as an example, the built-in electric field in the phase junction region was modulated via fabricating controllable anatase nanoparticles on rutile TiO2 surface to manipulate the interfacial contact area between anatase and rutile phases. We found that photocatalytic H2 evolution depends strongly on the interfacial contact area between anatase and rutile TiO2. The relation between the anatase/rutile phase.junction interfacial contact area and the specific photocatalytic activity shows a typical volcano curve, that is, increasing the interfacial contact area results in enhancement of the driving force for spatial charge separation, allowing more electrons and holes to migrate to the surface and participate in redox.reactions, but further increasing the interfacial contact area leads to decline of photocatalytic activity. The optimized interfacial contact is the most favorable balance between the strength of built-in electric field and transfer distance for photogenerated charge carriers for separation and transfer of photogenerated.electrons and holes at the phase junction region. Our work provides new insight into the construction of built-in electric fields on the surface of semiconductor-based photocatalysts to boost spatial charge separation for solar energy conversion systems.