Successful integration of defective heterojunctions is a proven effective strategy for promoting carrier separations and strengthening surface-interface redox reactions. Dipole moment variations are beneficial for charge carrier separation due to enlarged polarizations, especially within defective ones. Herein, motivated by the dipole variations in BiVO₄ and the unique layered structure of BiOCl, defective BiVO₄/BiOCl heterojunctions were designed and integrated. The as-integrated samples displayed unique nanosheets with thicknesses decreasing from 7.24 to 2.77 nm, resulting in the simultaneous formation of stable surface defects. The heterojunctions were investigated for the removal of dilute NO (∼ppb) under visible light and exhibited 1.85- and 2.05-folds enhanced efficiencies (75%), synchronous inhibition of NO₂ (16.7% selectivity) and a more positive DeNO_x index (0.36) than their constituent monomers. The improved activities and stabilities of surface defects were further examined by multi-run NO removal and EPR. The NO conversion products were validated by in situ DRIFTS investigation, which showed remarkable NO oxidation into NO₃⁻ and synchronous NO₂ inhibition in thinner defective BiVO₄/BiOCl. Mechanistic investigations indicated that surface defects in heterojunctions not only contributed to the improved light absorption and massive production of active species by coupling suitable band alignments, prolonging the carrier lifetime (3.55 ns to 7.52 ns) but also facilitated strong interfacial electric field contact at the junction interface of monomers, which enabled the construction of a direct Z-scheme charge transfer mechanism for NO removal.

中文翻译：

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用于可见光NO去除的超薄缺陷异质结：微观结构与反应机制之间的相关性


有缺陷的异质结的成功集成是促进载流子分离和加强表面界面氧化还原反应的有效策略。由于极化扩大，偶极矩变化有利于载流子分离，尤其是在有缺陷的极化中。在此，受 BiVO ₄ 偶极子变化和 BiOCl 独特的层状结构的启发，设计并集成了有缺陷的 BiVO ₄ /BiOCl 异质结。集成样品显示出独特的纳米片，厚度从 7.24 纳米减小到 2.77 纳米，从而同时形成稳定的表面缺陷。研究了异质结在可见光下去除稀 NO (∼ppb) 的能力，并表现出 1.85 倍和 2.05 倍的增强效率 (75%)、同步抑制 NO ₂ （16.7% 选择性）和比其组成单体更正的 DeNO _x 指数 (0.36)。通过多次 NO 去除和 EPR 进一步检查了表面缺陷活性和稳定性的改善。通过原位 DRIFTS 研究验证了 NO 转化产物，结果显示，在稀释剂缺陷 BiVO ₄ 并同步抑制 NO ₂ > /BiOCl。机理研究表明，异质结中的表面缺陷不仅有助于通过耦合合适的能带排列来提高光吸收和大量产生活性物质，延长载流子寿命（3.55 ns至7.52 ns），而且还促进了结处的强界面电场接触单体界面，这使得能够构建用于去除 NO 的直接 Z 型电荷转移机制。