Potassium cyamelurate K-3[C6N7O3] rod: A new visible-light photocatalyst for homogeneous/heterogeneous degradation of antibiotics

As a salt of cyameluric acid and a derivative of tri-s-triazine, rod-shaped potassium cyamelurate K-3[C6N7O3] has been synthesized and employed as a homogeneous photocatalyst for photodegradation of aquatic tetracycline hydrochloride (TC-HCl) under visible-light irradiation for the first time. The water-soluble K3[C6N7O3] owns excellent visible-light-driven photocatalytic activity, which is approximately 9 and 10 times higher than those on melon and g-C3N4 in water, respectively. The photocatalytic process is investigated experimentally and theoretically, and the active centers of K-3[C6N7O3] are identified by first principles calculations. The active radicals for the photodegradation are identified and a reaction mechanism is proposed. Moreover, K-3[C6N7O3] can also work as an efficiently heterogeneous photocatalyst for the removal of TC-HCl in ethanol. This work provides a novel photocatalyst bridging homogenous and heterogeneous photocatalysis for environmental protection and opens a new application space for alkali cyanurates.