Enhanced photocatalytic degradation of Cr (VI) and organic pollutants using novel 3D/2D MoS2/SnS2 heterostructures for water remediation

Abstract In this study, 3D flower-like MoS 2 nanostructures were synthesized using a hydrothermal technique to form heterostructures with 2D porous SnS 2 nanosheets. The resulting 3D/2D MoS 2 /SnS 2 heterostructures were evaluated for their photocatalytic abilities in removing Cr (VI), tetracycline (TC), and methylene blue (MB) under simulated solar irradiation. The results demonstrate that the MoS 2 /SnS 2 heterostructures significantly outperformed pristine MoS 2 and SnS 2 in photocatalytic efficiency. Specifically, the MoS 2 /SnS 2 photocatalysts achieved 99.9% degradation of Cr (VI) within 50 min, 96% degradation of TC in the same timeframe, and 99.9% elimination of MB in just 10 min. The reduction rate constant for Cr (VI) reduction by MoS 2 /SnS 2 photocatalysts was 0.117 min −1 , surpassing that of pure SnS 2 (0.007 min −1 ) and MoS 2 (0.0034 min −1 ) by 16 and 30 times, respectively. This outstanding performance is attributed to the heterojunction formation between SnS 2 and MoS 2 , which suppresses the recombination of photogenerated charge carriers and provides abundant reactive sites due to their large specific surface area. The proposed photodegradation mechanism illustrates the facilitated migration of photogenerated charge carriers under light irradiation, enabled by the energy band alignment at the MoS 2 /SnS 2 interface. These findings represent a significant advancement in the development of photocatalysts based on 3D flower-like MoS 2 and porous SnS 2 nanostructures, offering promise for applications in wastewater treatment and environmental remediation.