In this report, the photocatalytic and electrochemical activity of ZnO and ZnO/CdO nanocomposites were determined. Pure ZnO and nanocomposite ZnO/CdO were prepared by a vapor to solid mechanism and were characterized by different physical and chemical techniques. The CdO-modified ZnO possessed high efficiency to degrade textile effluent. It also showed high efficiency of degradation, such as 98% for methylene blue and 93% for methyl orange. Cadmium oxide (impurity) plays an important role in achieving zinc oxide materials that exhibit UV to visible light degradation of textile effluent. Additionally, uric acid sensing performed to study the electrochemical activity revealed that ZnO/CdO (90:10) nanocomposite produced high anodic currents, and these results were in agreement with the cyclic voltammetry reports.