Band Gap Energies and Photocatalytic Properties of CdS and Ag/CdS Nanoparticles for Azo Dye Degradation

CdS nanoparticles were synthesized by the ultrasonic‐assisted sol‐gel method and characterized by X‐ray diffraction (XRD). The Ag‐doped CdS (Ag/CdS) nanoparticles were also synthesized by the ultrasonic‐assisted sol‐gel method and characterized by XRD, X‐ray fluorescence spectrometry, scanning electron microscopy, and energy‐dispersive X‐ray analysis. The calculated sizes and experimental results are in good agreement. The calculated band‐gaps of CdS and Ag/CdS were found to be 2.62 and 2.46 eV, respectively. Photocatalytic degradation of Direct Red 264 azo dye was investigated with CdS and Ag/CdS under UV‐C and visible light irradiation. Experimental results indicate that the degradation rate of DR 264 follows pseudo second‐order kinetics. Also, the intraparticle diffusion coefficients of CdS and Ag/CdS were determined.