Cen Yu-Lang, Shi Jun-Jie, Zhang Min, Wu Meng, Du Juan, Guo Wen-Hui, Zhu Yao-Hui
State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
State Key Laboratory for Artificial Microstructures and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China.
J Colloid Interface Sci. 2019 Jun 15;546:20-31. doi: 10.1016/j.jcis.2019.03.044. Epub 2019 Mar 15.
Searching for promising visible-light photocatalysts for overall water splitting into hydrogen and oxygen is a very challenging task to solve the energy crisis and environment pollution. The widely-used tantalate and niobate perovskite photocatalysts have two drawbacks, i.e., the large energy band gap (∼3.2-4.6 eV) and low electron (hole) mobility 10 (10) cm V s, which greatly limit their photocatalytic performance. Here, based on the powerful first-principles and accurate GW calculations, we design several novel two-dimensional (2D) Ruddlesden-Popper (RP) type (n = 1) perovskite oxynitrides ABON (A = Ca, Sr, Ba and B = Ta, Nb) and their bonded heterostructures and comprehensively investigate their interlayer coupling, electronic structures, transport and photocatalytic characteristics. We find that 2D ABON oxynitrides have a reduced direct band gap at Γ-point, especially for three-layer (3L) BaNbON and 1L-SrNbON/1L-BaNbON bonded heterostructure with the optimized band gap ∼2.0 eV. Compared with tantalate and niobate perovskite oxides, the electron (hole) mobility increases 1-2 orders of magnitude up to 10-10 (10-10) cm V s. A fast electron-hole vertical transport across the heterointerface and remarkable electron-hole separation can be realized in 1L-SrNbON/1L-BaNbON bonded heterostructure due to its strong interface Ba-O and Sr-O bonds and type-II band offset. Compared with the well-known photocatalysts, such as BiVO and MoS/g-CN, an improved optical absorption (8 × 10 cm) in ABON is obtained in the visible region. The 2D RP-type perovskite oxynitrides 3L-BaNbON and 1L-SrNbON/1L-BaNbON are powerful visible-light photocatalysts for overall water splitting.
寻找有前景的用于将水完全分解为氢气和氧气的可见光光催化剂，是解决能源危机和环境污染的一项极具挑战性的任务。广泛使用的钽酸盐和铌酸盐钙钛矿光催化剂有两个缺点，即大的能带隙（约3.2 - 4.6电子伏特）和低的电子（空穴）迁移率10（10）厘米²伏⁻¹秒⁻¹，这极大地限制了它们的光催化性能。在此，基于强大的第一性原理和精确的GW计算，我们设计了几种新型二维（2D）Ruddlesden-Popper（RP）型（n = 1）钙钛矿氧氮化物ABON（A = Ca、Sr、Ba且B = Ta、Nb）及其键合异质结构，并全面研究了它们的层间耦合、电子结构、输运和光催化特性。我们发现二维ABON氧氮化物在Γ点处直接带隙减小，特别是对于三层（3L）BaNbON和1L-SrNbON/1L-BaNbON键合异质结构，其优化后的带隙约为2.0电子伏特。与钽酸盐和铌酸盐钙钛矿氧化物相比，电子（空穴）迁移率提高了1 - 2个数量级，达到10⁻¹⁰（10⁻¹⁰）厘米²伏⁻¹秒⁻¹。由于其强界面Ba - O和Sr - O键以及II型能带偏移，在1L-SrNbON/1L-BaNbON键合异质结构中可以实现电子 - 空穴的快速垂直跨界面传输和显著的电子 - 空穴分离。与著名的光催化剂如BiVO₄和MoS₂/g-C₃N₄相比，ABON在可见光区域获得了改善的光吸收（8×10⁻⁵厘米⁻¹）。二维RP型钙钛矿氧氮化物3L-BaNbON和1L-SrNbON/1L-BaNbON是用于水完全分解的强大可见光光催化剂。
