Preparation and heterogeneous photocatalytic activity of mesoporous H 3PW 12O 40/ZrO 2 composites

Abstract

A series of mesoporous zirconia supported Keggin units with different H 3PW 12O 40 loading levels (5–20 wt.%) and phase structures (amorphous, tetragonal, and the mixed phases of tetragonal and monoclinic) are prepared by a modified wet impregnation method. The phase structures, chemical structures, optical absorption properties, surface physicochemical properties, and morphologies of the composites are well-characterized via X-ray diffraction (XRD) patterns, FT-IR spectroscopy, Raman scattering spectroscopy, UV–vis diffuse reflectance spectroscopy (UV–vis/DRS), nitrogen adsorption/desorption determination, and field emission scanning electron microscopy (FESEM), indicating that the primary Keggin structure remained intact after formation of the composites, and impregnation of the Keggin unit into the surface of ZrO 2 framework has an influence on the electronic properties of the ZrO 2. The heterogeneous photocatalytic activity of as-prepared composites is studied via the model reactions of degradation of an aqueous 4-nitrophenol (4-NP) and dye methylene blue (MB) under aerobic condition, indicating that the photocatalytic activity of the composites was influenced by the factors such as phase structures, optical absorption properties, and surface physicochemical properties of the composites.