Highly active Cs2SnCl6/C3N4 heterojunction photocatalysts operating via interfacial charge transfer mechanism

In this study, a novel lead-free perovskite heterojunction Cs 2 SnCl 6 /C 3 N 4 composite was constructed and applied for photocatalytic NO purification. After design optimization, the Cs 2 SnCl 6 /C 3 N 4 heterojunction exhibit excellent and stable photocatalytic NO purification ability under visible-light irradiation, which is significantly better than pristine Cs 2 SnCl 6 and C 3 N 4 . Combined in-situ DRIFTS and electron spin resonance spin-trapping, the mechanism of Cs 2 SnCl 6 /C 3 N 4 photocatalytic NO removal was revealed. Under visible-light irradiation, the photo-generated electrons on the conduction band of C 3 N 4 would spontaneously migrate to the CB of Cs 2 SnCl 6 , leaving holes (h + ) on the valence band of C 3 N 4 , contributing to efficiently segregated charge carriers and improved photocatalytic NO purification. Density functional theory calculations also revealed the directional electron transfer at the C 3 N 4 and Cs 2 SnCl 6 interface, in which the charge was migrated from C 3 N 4 to Cs 2 SnCl 6 induced by the internal electric field . This research sheds fresh light on the fabrication of Cs 2 SnCl 6 /C 3 N 4 heterojunctions as well as its effective interfacial charge separation.