Zn–Cr layered double hydroxide: Visible light responsive photocatalyst for photocatalytic degradation of organic pollutants

Heterogeneous photocatalysis, one of the important steps in advanced oxidative process (AOPs) that was found to be promising for the elimination of toxic organic and inorganic compounds from wastewater. Herein, we reported Zn–Cr-CO3, a novel layered double hydroxide (LDH) for visible-light-driven photocatalytic degradation of organic chemicals. The physicochemical properties of the synthesized Zn/Cr-CO3 LDH, prepared by co-precipitation method at constant pH, were determined by several techniques such as powder X-ray diffraction (PXRD), Fourier Transform Infrared (FT-IR), thermo gravimetric/differential thermal analysis (TG/DTA), BET surface area, scanning electronic microscope (SEM), transmission electron microscope (TEM) and optical absorption spectra. The photocatalytic degradation studies on xanthene dyes (Rhodamine B, Rhodamine 6G) and substituted phenol (4-chloro 2-nitro phenol) using Zn–Cr-CO3 were reported here for the first time. The kinetic study demonstrated that Zn–Cr-CO3 LDH was an efficient photocatalyst for degradation of organic pollutants. The formation of intermediate oxidative species (OH, O2- and 1O2) during the photocatalytic reactions were ascertained by using different quenchers and the possible mechanism was proposed.

► Zn–Cr-CO3 LDH is synthesized by ion exchange method.
► Photocatalytic degradation of organic pollutants.
► The role of interlayer carbonate in photocatalytic activities has been explained.
► The roles of various oxidative species are examined.