Searching photocatalysts with sufficient utilization of sunlight and elucidating relevant reaction mechanism are still grand challenges in the field of semiconductor photocatalysis. Herein, we developed a strategy towards morphology tailoring in conjunction with oxygen vacancy in the structure of double perovskite CaCu₃Ti₄O₁₂. Cube, polyhedron, nanorod and octahedron shaped CaCu₃Ti₄O₁₂ morphologies were obtained by varying the salt composition during molten salt synthesis, and their visible-light photocatalytic capacities were tested for degrading an antibiotic, tetracycline. The degradation process follows a first-order kinetics, and excellent photooxidation performance was observed for octahedron and nanorod shaped CaCu₃Ti₄O₁₂ giving degradation rate constants of 1.14 × 10⁻¹ min⁻¹ and 8.40 × 10⁻² min⁻¹, respectively, much higher than those of polyhedron and cube shapes (their rate constants were 5.10 × 10⁻² min⁻¹ and 2.80 × 10⁻² min⁻¹, respectively). The improved photoefficiency could be attributed to high abundant oxygen vacancies, surface properties, charge transfer and enhanced carrier separation due to the synergetic roles of active species, as is supported by active species trapping experiments and theoretical simulations. The detailed mechanism was proposed on the basis of crystal structure, unique morphology and spin trapping experiment, which reveals the roles of various active species for efficiency enhancement. The enhanced efficiency was further elucidated by theoretical investigations of density functional theory (DFT) calculations on the adsorption between tetracycline and CaCu₃Ti₄O₁₂. The findings reported here not only provide a green and rational design of high-performance photocatalysts but also show the applications ranged from catalysis to mitigation of polluted environment.

中文翻译：

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氧空位诱导形态可控的CaCu ₃ Ti ₄ O ₁₂可见光降解抗生素的光催化活性

寻找足够利用太阳光的光催化剂并阐明相关的反应机理仍然是半导体光催化领域中的巨大挑战。在这里，我们开发了一种在钙钛矿型CaCu ₃ Ti ₄ O ₁₂的结构中结合氧空位对形态进行剪裁的策略。立方体，多面体，纳米棒和八面体形的CaCu ₃ Ti ₄ O ₁₂通过改变熔融盐合成过程中盐的组成来获得形态学，并测试了它们的可见光光催化能力以降解抗生素四环素。降解过程遵循一级动力学，对于八面体和纳米棒状CaCu ₃ Ti ₄ O ₁₂，观察到优异的光氧化性能，降解速率常数分别为1.14×10 ^-1  min ^-1和8.40×10 ^-2  min ^-1，分别高于多面体和立方体形状（它们的速率常数分别为5.10×10 ^-2  min ^-1和2.80×10 ^-2  min ^-1， 分别）。活性物种的诱捕实验和理论模拟支持，归因于活性物种的协同作用，光效率的提高可归因于高丰富的氧空位，表面性质，电荷转移和增强的载流子分离。在晶体结构，独特的形貌和自旋俘获实验的基础上，提出了详细的机理，揭示了各种活性物质对提高效率的作用。密度泛函理论（DFT）计算理论对四环素与CaCu ₃ Ti ₄ O ₁₂吸附的理论研究进一步阐明了提高的效率。。此处报道的发现不仅为高性能的光催化剂提供了绿色合理的设计，而且还显示了从催化到减轻污染环境的各种应用。