Carbon dots decorated the exposing high-reactive (111) facets CoO octahedrons with enhanced photocatalytic activity and stability for tetracycline degradation under visible light irradiation

Abstract

Octahedral CoO with exposed high-reactive (111) facets holds a promising noble-metal-free material in the photocatalysis. However, the (111) facet is usually unstable and easily deactivated during the photocatalytic process as the result of its poloar catastrophe. In this work, carbon dots (CDs) as co-catalyst modified and stabilized the (111) facets of CoO octahedrons (CDs-CoO) were prepared by one-step solvothermal method. The desired CDs-CoO shows the excellent photocatalytic activity and well stability. Meanwhile, the CDs-CoO (5wt.%) composite exhibits the highest photocatalytic activity for degradation of tetracycline (87%, 60min), and presents remarkable photostability after five successive cycles (5h). This enhanced photocatalytic activity and outstanding stability in CDs-CoO composites could be ascribed to several merits of CDs that not only improve charge separation efficiency but also strengthen the interaction between CDs and high-reactive (111) facets of CoO octahedrons.