Abstract

Heteropolyacid supported ZrO2 nanocomposites has been prepared through wet impregnation method with the intention to improve the photodegradation performance under UV light. The material consist of mixed monoclinic and cubic ZrO2 phase and orthorhombic Keggin type 12- phosphotungstic acid(PTA) with different ratios. The phase structure, chemical composition and oxidation state of the elements tungsten (W), zirconia (Zr) were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In addition, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Diffuse Reflectance Ultraviolet-Visible Spectroscopy (DRS-UV-Vis) were carried out to confirm the presence of functional group and optical absorption properties. Surface area of the synthesized composite was analyzed by BET analysis and morphology was confirmed using high resolution scanning electron microscopy (HR-SEM) and high resolution transmission electron microscopy (HR-TEM) and the results reveal that PTA is chemically bonded to zirconia support which confirms that the sample was synthesized successfully. The heterogeneous photocatalytic activity of the composites were studied by using aqueous solution of various organic pollutants such as methylene blue (MB), methyl orange (MO), rhodamine B (Rh-B), crystal violet (CV), bromo cresol green (BCG) dyes, 4- Nitrophenol and 2,4-Dichlorophenoxy acetic acid under UV light illumination. It is found that each dye needs different specific ratio of nanocomposite to degrade efficiently at a given time interval.