Photocatalytic degradation of phenol and its derivatives over ZnFe layered double hydroxide

A simple co-precipitation method was employed for synthesizing ZnFe-CO3 layered double hydroxide (LDH) and characterized through powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), UV − visible diffused reflectance spectroscopy (UV–vis DRS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and N2 adsorption–desorption measurement. The catalytic activity was then investigated for photodegradation of phenol and its derivatives under both visible and UV light irradiations. The catalyst exhibited enhanced photocatalytic activity towards the degradation of various phenolic compounds under visible light irradiation compared to UV light. The effect of various reaction parameters such as catalyst amount, initial concentration of phenolic compounds and pH of the solutions on the photodegradation process was also studied thoroughly. The reaction kinetics was analyzed by Langmuir-Hinshelwood first order kinetic model. The plausible mechanism and degradation pathway of photocatalytic degradation of phenolic compounds were also discussed in detail. In addition, we investigated reaction pathways and thermochemistry for the degradation of phenol initiated by OH radicals using Density Functional Theory. The photocatalyst was stable and active up to four successive cycles.