Efficient photodegradation of 4-chlorophenol under solar radiation using a new ZnO/ZnS/carbon xerogel composite as a photocatalyst

Abstract This paper explored the development of a new zinc oxide/zinc sulfide/carbon xerogel composite photocatalyst aiming at the efficient 4-chlorophenol photodegradation under solar light. X-ray diffractometry highlights that the crystalline structure of zinc sulfide depended on the presence of zinc oxide, changing from face-centered cubic in the pure ZnS to hexagonal (2 H) in the composite. Furthermore, the addition of carbon xerogel to the composite led to a reduction in the particle size and an increase in the specific surface area. Photocatalytic results show that the ternary composite (XC/ZnO-ZnS) displayed the best photocatalytic response for 4-chlorophenol degradation among the tested materials. Such photocatalytic improvement is probably related to the formation of heterojunctions between the semiconductors and the carbonaceous phase, as well as the enhanced morphological properties of the composite. The superiority of the XC/ZnO-ZnS was further corroborated in the chronoamperometry tests, as it presented the highest photocurrent generation.