Synthesis of CdS-SnS photocatalyst by chemical co-precipitation for photocatalytic degradation of methylene blue and rhodamine B under irradiation by visible light

The development of photocatalysts for use in degrading hazardous dyes has attracted significant attention. In this study, a CdS-SnS heterostructure was synthesized to promote the photocatalytic activity of visible light-driven pure CdS. The diffuse reflectance and photoluminescence spectra indicated a narrow band gap (2.04 eV) and the fast transfer and separation of charges in CdS-SnS (Sn/Cd = 1). Electrochemical impedance spectroscopy demonstrated that the transfer of charge carriers was accelerated more in CdS-SnS (Sn/Cd = 1) (Z ' = 13 k omega) than CdS-SnS (Sn/Cd = 1/3) (Z ' = 15 k omega) and CdS (Z ' = 50 k omega). The ultraviolet-visible absorption spectra showed that the photodegradation of methylene blue (MB) improved from 80% with CdS to 92% and 99% using CdS-SnS with Sn/Cd = 1/3 and 1, respectively. The photodegradation of rhodamine B (RhB) improved from 67% with CdS to 95% and 99% using CdS-SnS with Sn/Cd = 1/3 and 1, respectively. The effects of various parameters on photodegradation were also investigated. This study investigated the performance of CdS-SnS in the photo -degradation of MB, RhB, and phenol for the first time. The photodegradation and absorption kinetics were described via pseudo-first order and pseudo-second order kinetics to obtain adsorption capacities for CdS-SnS (Sn/Cd = 1) of 35.84 and 26.88 mg/g in MB and RhB solutions, respectively.