Synthesis and characterisation of MoS2-CdS catalyst for photocatalytic degradation of methylene blue from aqueous solution

Abstract

A new approach has been developed for the fabrication of visible light photocatalysts. MoS2-CdS binary catalysts with good crystalline structure were prepared by the hydrothermal method. Single CdS and MoS2 catalysts were also synthesised by the hydrothermal method to compare the degradation efficiency results. The structure and size of all the samples were analysed by XRD. The results showed that hydrothermal treatment is an effective method to prepare MoS2-CdS binary catalysts and single CdS catalysts of hexagonal structure. Using UV-Vis reflectance spectra, the bandgap energies of MoS2-CdS binary catalysts and single CdS catalysts were estimated to be in the range of 2.37-2.62 eV and 2.27-2.38 eV, respectively. Higher degradation efficiency was achieved by adding a co-catalyst (MoS2) to the CdS catalysts, compared with the single CdS catalysts. In this case, the degradation efficiency of CdS-Na2S increased from 66% to 75% with addition of MoS2 after 4 h irradiation time.