ZnWO4 photocatalysts with various morphologies were synthesized by a template-free hydrothermal synthesis process. The morphologies had a significant influence on the photocatalytic activity for methylene blue and Rhodamine B degradation. ZnWO4 nanorods with a highly [1 0 0] preferred orientation. obtained at pH 10, exhibited the highest photocatalytic activity among all the samples. This kind of nanorods had the most planes along the [1 0 0] direction-(0 1 0) and (0 1 1) planes, which meant most (0 1 0) and (0 1 1) planes exposed in ZnWO4 phase. Basis on the analysis of crystal plane and hydrogen-related defects, the (0 1 0) and (0 1 1) planes could speculate to be more active for photodegradation. (C) 2010 Elsevier B.V. All rights reserved.