Facile synthesis, optical properties regulation and boosted photocatalytic degradation performance for organic pollutants of Mn:CuInS2/CdS nanocrystals

Abstract

In this work, 3-mercaptopropionic acid (MPA) coated transition metal ions doped CuInS2/CdS nanocrystals were synthesized by using a facile, green and safe chemical solution method combined with epitaxy growth technology. By changing the concentration of Mn2+ and adjusting the microstructure and properties of CuInS2/CdS based nanocrystals, nanocrystals with specific phase structure, composition, scale and optical properties were obtained. The largest PL quenching was observed in Mn:CuInS2/CdS, which may be due to the significantly improved photogenerated charge transfer between Mn and CuInS2/CdS. The results show that doping of Mn into the lattice of CuInS2/CdS obviously decreases the crystal size, changes band gap and improves visible light absorption capability. The photocatalytic degradation of rhodamine B (RhB) solution by nanocrystals was tested under visible light. The results show that the highest degradation efficiency was achieved when the doping concentration was x = 0.05. We believe that heterojunction is beneficial to improve the separation efficiency of photogenerated carriers and the application of nanocrystals in the visible light region. In addition, the introduction of doped ions in nanocrystals can not only promote the formation of defects or the change of energy bands, but also improve the separation efficiency of photogenerated carriers. From the free radical trapping experiments, we find that h+ is the main active species in the photocatalytic degradation of RhB by CuInS2/CdS nanocrystals. This study will provide an important scientific reference for the development and utilization of new water antifouling materials.