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 MoS2 nanostructures were synthesized using a hydrothermal technique to form heterostructures with 2D porous SnS2 nanosheets. The resulting 3D/2D MoS2/SnS2 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 MoS2/SnS2 heterostructures significantly outperformed pristine MoS2 and SnS2 in photocatalytic efficiency. Specifically, the MoS2/SnS2 photocatalysts achieved 99.9% degradation of Cr (VI) within 50 minutes, 96% degradation of TC in the same timeframe, and 99.9% elimination of MB in just 10 minutes. The reduction rate constant for Cr (VI) reduction by MoS2/SnS2 photocatalysts was 0.117 min−1, surpassing that of pure SnS2 (0.007 min−1) and MoS2 (0.0034 min−1) by 16 and 30 times, respectively. This outstanding performance is attributed to the heterojunction formation between SnS2 and MoS2, 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 MoS2/SnS2 interface. These findings represent a significant advancement in the development of photocatalysts based on 3D flower-like MoS2 and porous SnS2 nanostructures, offering promise for applications in wastewater treatment and environmental remediation.