Direct Z-scheme palladium tetranapthalene porphyrin/C3N5 heterojunction for efficient photocatalytic degradation of high concentration dyes and antibacterial performances

This study presents the synthesis and characterization of palladium tetranapthalene porphyrin/C 3 N 5 -x [(Np) 4 PdP/CN-x, x is the mass ratio] heterojunctions fabricated by a wet grinding technology. The key focus is to effectively separate the electron-hole (e − -h + ) produced by C 3 N 5 after illumination to improve its photocatalytic activity. By incorporating palladium tetranapthalene porphyrin [(Np) 4 PdP] as photosensitizer, a Z-scheme charge carriers migration mechanism is introduced to facilitate the separation of photogenerated carriers. Through optimization, the photocatalytic performance of (Np) 4 PdP/CN-x nanocomposites were evaluated, revealing that (Np) 4 PdP/CN-1 exhibits the most superior activity, achieving an impressive 98.73 % and 99.87 % degradation efficiency of 20 ppm methylene blue (MB) and rhodamine B (RhB) under a 300 W xenon lamp within 13 min. We also studied the photocatalytic antibacterial properties of (Np) 4 PdP/CN-1, and the inhibition rates of Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) reached 96.41 % and 98.14 % within 10 min. Free radical capture tests and electron paramagnetic resonance measurements indicated that ·O 2 – and ·OH were the primary active substances during photodegradation. On the basis of that, a feasible photodegradation mechanism of direct Z-scheme heterojunction was proposed. This study provides a possibility for designing C 3 N 5 based materials modified with metal porphyrins for photocatalytic dye degradation and antibacterial.