Influence of ZnWO4nanorod aspect ratio on the photocatalytic activity

Abstract

ZnWO₄ nanorod photocatalysts with various aspect ratios were synthesized by a hydrothermal method. The aspect ratio of the ZnWO₄ nanorods was governed by the hydrothermal temperature and pH value. ZnWO₄ nanorod photocatalysts showed highly efficient photocatalytic activity for the degradation of methylene blue under ultraviolet light irradiation. The photocatalytic activity and the effective separation of photogenerated electron–hole pairs were promoted by the increasing aspect ratio of the ZnWO₄ nanorods. The amount of electron donors in the ZnWO₄ increased with the aspect ratio of ZnWO₄, which was in good agreement with photocurrent results. The enhancement of photocurrent density and photocatalytic activity resulted from the reduction of charge-transfer resistance and capacitive reactance, which were deduced by the high aspect ratio of ZnWO₄ nanorods.