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

摘要

ZnWO_4 (sanmartinite) powders were produced by mechanochemical synthesis using ZnO andWO_3 at 700 rpm for 25, 50 and100 min, respectively. SEM indicated the ratio of sub-micron-sized ZnWO_4 particles was raised, and particle size distributionwas homogenized by increasing process time. XRD results revealed the formation of sanmartinite after 100 min milling with700 rpm. Raman Spectroscopy confirmed the XRD results except detection of WO_3 and ZnO traces. The surface area of thesamples 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 eVwith further process time. Under the visible light, the highest photocatalytic efficiency for degradation of malachite greendyes was observed in sample ball milled at 700 rpm for 25 min. Samples ball milled at 700 rpm for 100 min have lowerphotocatalytic activity compared to samples ball milled at 700 rpm 25 and 50 min. The efficiency of photocatalytic activitieschanged from 45 to 83% after 120-min photocatalysis process. It is possible to claim that ZnWO_4 powders are promisingphotocatalyst.