Synthesis of a CoO-ZnO photocatalyst for enhanced visible-light assisted photodegradation of methylene blue

The synthesis of efficient photocatalysts for visible light-assisted photodegradation of aqueous phase organic pollutants has received significant consideration recently. In this research, Co-doped ZnO is synthesized by the precipitation method for enhanced visible-light assisted photodegradation of methylene blue. The XRD and XPS analyses showed that Co exists in a divalent state in the as-prepared composite. The UV-visible DRS analyses showed that incorporation of Co2+ in the ZnO structure greatly enhanced the visible light absorption due to its photosensitizing effect. Analyses of reaction mixtures showed about 9, 64, 96, and 79% degradation of methylene blue in the presence of pure ZnO, 5% CoO-ZnO, 10% CoO-ZnO, and 15% CoO-ZnO, respectively. The photodegradation of methylene blue is described using the Langmuir-Hinshelwood mechanism.