Visible Photocatalytic Activity Enhancement of ZnWO4 by Graphene Hybridization

ZnWO4/graphene hybride (GZW-X) photocatalysts were synthesized via a facile in situ reduction of graphene oxide and ZnWO4 in water. High efficiency for the degradation of methylene blue (MB) under both UV light and visible light was obtained for the GZW-X photocatalysts. The photocatalytic efficiency of ZnWO4/graphene-0.2 wt % under visible-light and UV-light irradiation was ∼7.1 and 2.3 times that of pristine ZnWO4, respectively. The visible photocatalytic activity originated from the •OH and O2•–, which were formed by photosensitization of graphene in ZnWO4/graphene. The enhancement of UV photocatalytic light activity in ZnWO4/graphene was attributed to the high separation efficiency of photoinduced electron–hole pairs resulting from the promotion of HOMO orbit of graphene in ZnWO4/graphene.