Effects of Fe3+ substitution on Zn-Al layered double hydroxides for enhanced NO photochemical abatement

Abstract

In this work the ability of ZnAlFe-CO3 layered double hydroxides (LDHs) as highly efficient UV-Vis light photocatalysts for the photochemical oxidation of NO gas was studied. LDHs with 3.5 to 4.1 M2+/M3+ and 0.33 to 1.55 Fe/Al ratios were prepared by a coprecipitation method. The samples were characterized by different techniques such as XRD, XPS, FT-IR, ICP-MS, TG, SBET, SEM and Diffuse reflectance (DR). The increased presence of the Fe3+ ions gave rise to changes in the structure, morphology and optical properties of the LDHs. The prepared ZnAlFe-CO3 systems exhibited increased surface area and enhanced visible-light absorbance. The photochemical NO abatement resulted in outstanding conversion efficiency (56 %) and selectivity (93 %) for the iron containing samples, due to a decrease of the e-/h+ recombination, higher generation of ⋅O2- and ⋅OH radicals and their NO2 adsorption ability.