In this study, a novel lead-free perovskite heterojunction Cs₂SnCl₆/C₃N₄ composite was constructed and applied for photocatalytic NO purification. After design optimization, the Cs₂SnCl₆/C₃N₄ heterojunction exhibit excellent and stable photocatalytic NO purification ability under visible-light irradiation, which is significantly better than pristine Cs₂SnCl₆ and C₃N₄. Combined in-situ DRIFTS and electron spin resonance spin-trapping, the mechanism of Cs₂SnCl₆/C₃N₄ photocatalytic NO removal was revealed. Under visible-light irradiation, the photo-generated electrons on the conduction band of C₃N₄ would spontaneously migrate to the CB of Cs₂SnCl₆, leaving holes (h⁺) on the valence band of C₃N₄, contributing to efficiently segregated charge carriers and improved photocatalytic NO purification. Density functional theory calculations also revealed the directional electron transfer at the C₃N₄ and Cs₂SnCl₆ interface, in which the charge was migrated from C₃N₄ to Cs₂SnCl₆ induced by the internal electric field. This research sheds fresh light on the fabrication of Cs₂SnCl₆/C₃N₄ heterojunctions as well as its effective interfacial charge separation.

本研究构建了一种新型无铅钙钛矿异质结 Cs ₂ SnCl ₆ /C ₃ N ₄复合材料，并将其应用于光催化 NO 净化。经过设计优化，Cs ₂ SnCl ₆ /C ₃ N ₄异质结在可见光照射下表现出优异且稳定的光催化NO净化能力，明显优于原始Cs ₂ SnCl ₆和C ₃ N ₄。结合原位漂移和电子自旋共振自旋俘获，Cs ₂ SnCl _6的机理揭示了/C ₃ N ₄光催化NO去除。在可见光照射下，C ₃ N ₄导带上的光生电子会自发迁移到 Cs ₂ SnCl _{6的 CB 上，在 C 3} N ₄的价带上留下空穴（h ⁺ ） ，有助于有效分离电荷载流子和改进的光催化 NO 净化。密度泛函理论计算还揭示了 C ₃ N ₄和 Cs ₂ SnCl ₆界面处的定向电子转移，其中电荷从 C 迁移₃ N ₄到 Cs ₂ SnCl ₆由内部电场感应。该研究为 Cs ₂ SnCl ₆ /C ₃ N ₄异质结的制备及其有效的界面电荷分离提供了新的思路。