Controllable construction of ZnWO4 nanostructure with enhanced performance for photosensitized Cr(VI) reduction

Structure controlled ZnWO 4 nanomaterials were fabricated by a facile hydrothermal reaction . The nanorod-like ZnWO 4 with exposed (111) facets exhibits significant promoting effect for Cr 6+ reduction than that of noncrystalline ZnWO 4 nanoparticles . Specifically, the photocatalytic performance of ZnWO 4 -T14 for Cr 6+ reduction is 9.8 times higher than that of ZnWO 4 -T0. The effect of Zn 2+ on the concentration-absorbance (C-A) curve of K 2 Cr 2 O 7 solution was evaluated and investigated systemically, and adding Zn 2+ can improve the UV–vis spectrum detection sensitivity of K 2 Cr 2 O 7 solution. Methylene blue (MB) as a photosensitizer to enhance the photocatalytic activity of ZnWO 4 for Cr 6+ reduction is reported for the first time. In particular, the photocatalytic activity of ZnWO 4 -T14 for Cr 6+ reduction is 96.7% in 10 mg/L MB solution, which is 65.1% higher than that in aqueous solution. Moreover, the ZnWO 4 -T14/MB possesses excellent stability, and the reduction rate of Cr 6+ remains above 90% after four cycles. We believe that the photosensitized strategy is a promising methodology in the treatment of heavy metal ion due to its superior photocatalytic activity and stability.