Construction of SnS2@C3N5 photocatalysts by self-assembly: in-depth analysis of the excellent photocatalytic performance and Z-scheme heterojunction carrier transfer mechanism

Abstract

Amidst global energy transition priorities and environmental remediation imperatives, heterointerface-engineered photocatalysts emerge as strategic foci in advanced materials development. In this study, SnS₂@C₃N₅ composite with Z-scheme heterojunction structure were prepared using a synergistic strategy of hydrothermal synthesis and electrostatic self-assembly. Systematic characterization and performance tests show its unique energy band matching and interfacial charge transport mechanism promote photogenerated carrier separation thus potentiate the catalytic performance under luminous incidence. The material demonstrates robust photocatalytic performance. In hydrogen production tests, the value reaches 7546 μmol g⁻¹ h⁻¹, demonstrating an 8.43-fold increase compared to pristine C₃N₅. For methyl orange degradation, it achieves 89.7 % removal efficiency within 120 min, being 2.2 times more effective than C₃N₅ and 4 times higher than SnS₂. Combined with transient photocurrent, fluorescence spectroscopy and theoretical calculations reveal the charge transfer pathways and reaction kinetics in Z-scheme heterojunctions. These findings provide both theoretical guidance and practical strategies for developing multifunctional photocatalytic materials.