[en] Highlights: • Z-scheme Bi₂WO₆/ZnIn₂S₄ composites show enhanced photocatalytic activity. • Zero-order kinetics and pseudo-first-order kinetics are observed at different stages of MO degradation. • Photocatalyst shows high degradation efficiency towards a different class of contaminants. As a potential candidate photocatalyst, high carrier recombination rate of ZnIn₂S₄ limits its application, and it is necessary to improve its performance by constructing suitable structure. In this study, Bi₂WO₆/ZnIn₂S₄ composites with Z-scheme structure were successfully prepared, and they show enhanced photocatalytic performance. The BWO/ZIS-2 shows the highest photocatalytic efficiency of 97.5% within 60 min for degrading methyl orange (MO), and maintain an efficiency of more than 90% after five reuses. Moreover, BWO/ZIS-2 can degrade various organic pollutants without selectivity. Rapid transfer of carriers inhibits the recombination of e⁻ and h⁺, which is responsible for high photocatalytic activity of Bi₂WO₆/ZnIn₂S₄.

[en] Photocatalysis has been rapidly developed as a sustainable technology to decompose contaminants by using photogenerated carriers excited through light irradiation. Electrons for molybdenum trioxide (MoO₃) semiconductor with wide band gap can be easily transferred to its conduction band via dye sensitization effect under visible light. However, MoO₃ still suffers from poor photocatalytic ability for organic dyes due to the low energy level of the conduction band and the insufficient utilization of the induced electrons. In this study, molybdenum dioxide (MoO₂) nanoparticles were decorated on the surface of MoO₃ nanobelts without requiring an additional Mo source by using a simple in-situ hydrothermal method. In the reaction process, the partial MoO₃ itself was reduced to metallic MoO₂ nanoparticles, and the resulting intimate interface between MoO₂ and MoO₃ could accelerate the transfer of dye sensitization-induced electrons. The as-prepared MoO₂/MoO₃ nanocomposites exhibited extremely enhanced visible light photocatalytic activity for decomposing rhodamine B (RhB) with the assistance of H₂O₂. The mechanism for high-efficiency degradation was analyzed and explored by conducting theoretical calculations and designing further experiments. The high-efficiency degradation might be due to the synergistic effect caused by the well-matched energy band structure between dyes and MoO₃, and the metallic MoO₂ nanoparticles, which can accelerate the production of hydroxyl radical (OH) from H₂O₂. OH is a dominant reactive species for the degradation of RhB under visible light irradiation.