The photocatalytic degradation and mechanism of rhodamine B by Zn–Al layered double hydroxide

Zn–Al layered double hydroxides (Zn–Al LDHs) with a typical layered structure were successfully synthesized by the hydrothermal method . The effects of molar ratios of Zn and Al on the structure, morphology, chemical composition and photocatalytic performance of Zn–Al LDHs were systematically investigated. By adjusting the Zn/Al molar ratio, it can be found that the Zn–Al-LDH-3 sheet with the ratio of 3 exhibits the best photocatalytic activity and reusability, which is mainly ascribed to the formation of more photo-generated holes in the photocatalytic process proved by the free radical quenching experiment. The optimized conditions of catalyst dosages, rhodamine B (RhB) concentrations and initial pH values to achieve the highest were also investigated in detail. This work provides a simple method for designing environmental friendly layered double hydroxide photocatalysts with special morphologies.