Preparation of ZnWO4 (Sanmartinite) Powder Through Mechanochemical Method for Visible Light-Induced Photocatalysis

Abstract

ZnWO4(sanmartinite) powders were produced by mechanochemical synthesis using ZnO and WO(3)at 700 rpm for 25, 50 and 100 min, respectively. SEM indicated the ratio of sub-micron-sized ZnWO(4)particles was raised, and particle size distribution was homogenized by increasing process time. XRD results revealed the formation of sanmartinite after 100 min milling with 700 rpm. Raman Spectroscopy confirmed the XRD results except detection of WO(3)and ZnO traces. The surface area of the samples was ranged between 3.65 and 4.05 m(2)/g. Optical band-gap energies of the samples increased from 2.68 to 2.86 eV with further process time. Under the visible light, the highest photocatalytic efficiency for degradation of malachite green dyes was observed in sample ball milled at 700 rpm for 25 min. Samples ball milled at 700 rpm for 100 min have lower photocatalytic activity compared to samples ball milled at 700 rpm 25 and 50 min. The efficiency of photocatalytic activities changed from 45 to 83% after 120-min photocatalysis process. It is possible to claim that ZnWO(4)powders are promising photocatalyst.