Utilizing semiconductors to catalyze the conversion of N₂ to NH₃ has brought great promise in alleviating the issue of energy shortage. However, the wide band gap and high recombination rate of photogenerated (e⁻/h⁺) charge restrict their photocatalytic efficiency. Herein, a novel catalyst, N-Black In₂O_3−x/InVO₄ was developed by coupling InVO₄ nanosheets into defect-rich N-Black In₂O_3−x nanorods to construct multiple heterojunctions using the NH₂-MIL-68(In) metal–organic-framework as a template. The N-Black In₂O_3−x/InVO₄ multiple heterojunctions with oxygen vacancies could expand the light absorption range, act as electron trap centers, promote the separation of photogenerated carriers, and significantly improve the adsorption as well as activation of N₂. Density functional theory (DFT) calculations revealed that the exposed (321) planes of the N-Black In₂O_3−x possess a higher surface energy than the (222) planes, which indicates that the exposed (321) planes can adsorb more N₂ molecules and transform them into NH₃ molecules. Consequently, owing to the efficient separation of photogenerated carriers, the nitrogen fixation rate of the N-Black In₂O_3−x/InVO₄ heterostructure was as high as 2.07 mmol g⁻¹ h⁻¹ without any organic scavengers and precious-metal cocatalysts, which was 20.7, 2.4, 2.1, and 1.8 times that of NH₂-MIL-68(In), N-In₂O₃, InVO₄, and N-Black In₂O_3−x, respectively.

中文翻译：

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用于高效光催化固定的新型 N-Black In2O3−x/InVO4 异质结：暴露的 (321) 面和氧空位的协同效应

利用半导体催化N ₂转化为NH ₃为缓解能源短缺问题带来了巨大希望。然而，宽带隙和光生（e ^- /h ⁺）电荷的高复合率限制了它们的光催化效率。在此，通过将 InVO ₄纳米片耦合到富含缺陷的 N-Black In ₂ O _{3- x}纳米棒中以使用 NH ₂ -MIL-构建多个异质结，开发了一种新型催化剂 N-Black In ₂ O _{3- x} /InVO ₄ 68(In) 金属-有机框架作为模板。N-Black In ₂具有氧空位的O _{3− x} /InVO ₄多重异质结可以扩大光吸收范围，充当电子陷阱中心，促进光生载流子的分离，并显着提高N ₂的吸附和活化。密度泛函理论 (DFT) 计算表明，N-Black In ₂ O _{3− x}的暴露 (321) 面具有比 (222) 面更高的表面能，这表明暴露的 (321) 面可以吸附更多N ₂分子并将它们转化为 NH ₃分子。因此，由于光生载流子的有效分离，N-Black In ₂ O _{3- x} /InVO ₄异质结构的固氮率高达2.07 mmol g ^-1 h ^{-1 且}不含任何有机清除剂和贵金属分别是 NH ₂ -MIL-68(In)、N-In ₂ O ₃、InVO ₄和 N-Black In ₂ O _{3- x 的}20.7、2.4、2.1和 1.8 倍。