Interfacial effect of the nanostructured Ag2S/Co3O4 and its catalytic mechanism for the dye photodegradation under visible light

Abstract

In this study, the synthesis of a highly hybrid, heterogeneously structured nanocomposite catalyst consisting of Ag2S nanoparticles dotted on a Co3O4 microrod array is reported. The average diameter and length of the Co3O4 microrods was optimized to be approximately 300nm and 20μm, respectively, and the average size of the Ag2S nanoparticles was approximately 10nm. When the Ag2S nanoparticles were deposited on the Co3O4 microrods, the characteristic optical band gap energy of Co3O4 decreased from 1.26eV to 1.23eV, and the intensity of the absorbance peak at 650nm increased significantly. The catalytic activity of nanosized Ag2S/Co3O4 for the photodegradation of organic contaminants with potassium hydrogen persulfate (PMS) or ozone (O3) was evaluated using basic green 1 dye (BG1) as a model pollutant. In the presence of the hybrid Ag2S/Co3O4 catalyst developed in this study, the complete photodegradation of the BG1 solution was achieved in 20min and 6min when PMS and O3 were used, respectively. In addition, the experimental results suggest that the catalytic photodegradation of BG1 using the Ag2S/Co3O4/PMS and Ag2S/Co3O4/O3 processes was dominated by the OH and O2− radicals, respectively.