Elemental doping at coherent interfaces is very difficult and rarely used to improve the interfacial properties since coherent interfaces have low interfacial energies and lack open space for trapping dopant atoms. Exploring universally applicable strategies for elemental doping at coherent interfaces represents an important progress in interface science and engineering. In this study, Nb atoms are successfully doped at coherent (001) LaAlO3/anatase-TiO2 interfaces, which enhances greatly the efficiency of photocatalytic hydrogen production from water. Transmission electron microscopy investigations reveal that both LaO- terminated and AlO2-terminated LaAlO3/anatase-TiO2 interfaces can trap two layers of Nb atoms, which accompanies with the formation of La vacancies between them. First-principles calculations suggest that Nb atoms segregate at the interfaces under the action of potential gradient, which increases significantly the strength of the built-in electric field in TiO2, thereby facilitating the separation of photogenerated carriers and improving the photocatalytic performance. The H2 production of the Nb doped coherent interface is about 4 times that of the pristine coherent interface. Since potential gradient widely exists at various interfaces including the coherent ones, elemental doping by potential gradient should be an universally applicable fabrication method for tuning the properties of interfaces and heterostructures.

中文翻译：

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Nb掺杂相干TiO2/LaAlO3界面：偏析机制和改进的光催化性能


相干界面处的元素掺杂非常困难，很少用于改善界面性能，因为相干界面的界面能量较低，并且缺乏捕获掺杂剂原子的开放空间。探索相干界面元素掺杂的普遍适用策略代表了界面科学和工程的重要进展。在这项研究中，在相干 （001） LaAlO3/锐钛矿-TiO2 界面上成功掺杂了 Nb 原子，这大大提高了从水中光催化制氢的效率。透射电子显微镜研究表明，LaO-封端和 AlO2 封端的 LaAlO3/锐钛矿-TiO2 界面都可以捕获两层 Nb 原子，这伴随着它们之间 La 空位的形成。第一性原理计算表明，在电位梯度的作用下，Nb 原子在界面处偏析，这显着增加了 TiO2 中内置电场的强度，从而促进了光生载流子的分离，提高了光催化性能。Nb 掺杂相干界面的 H2 产生量约为原始相干界面的 4 倍。由于电势梯度广泛存在于各种界面上，包括相干界面，因此通过电势梯度进行元素掺杂应该是调节界面和异质结构特性的一种普遍适用的制造方法。