Ternary MgAlFe-Layered Double Hydroxide: Synthesis, Characterization, and Application in Photocatalytic Degradation

In this study, MgAlFe-layered double hydroxide (LDH) was prepared using the co-precipitation method, and its performance as a photocatalyst for methylene blue (MB) degradation was evaluated. XRD and FTIR analyses confirmed the crystalline structure and successful incorporation of Al into the LDH layers. SEM and TEM images revealed a uniform morphology and layered structure and UV–vis DRS analysis showed that MgAlFe-LDH has an appropriate band gap for visible light absorption. Photoluminescence studies indicated good charge separation, reducing electron-hole recombination and enhancing photocatalytic performance. The effects of the Mg/Al/Fe molar ratio, illumination time, catalyst dosage, MB concentration, and pH on the degradation efficiency were examined. Optimized conditions of Mg/Al/Fe molar ratio 3:0.9:0.1, 180 min illumination, 10 mg L⁻¹ catalyst, 20 mg L⁻¹ MB, and pH 13 yielded a remarkable 90.4%  MB degradation efficiency. The primary active species in the photocatalytic reaction were identified as hydroxyl radicals (·OH) and holes (h⁺). The incorporation of ternary LDH enhances the photocatalytic performance due to its high stability, versatility, and ability to integrate multiple metal cations. This study broadens the application of LDH in treating organic dye wastewater and provides new insights into the photocatalytic degradation of MB.