Preparation of highly uniform 1-dimensional α-Ag2WO4 nanostructures with controllable aspect ratio and study of the growth mechanism

Abstract

The synthesis of α-Ag₂WO₄ crystals using conventional methods typically leads to large micrometer-sized and/or non-uniform products. In this study, we demonstrate the preparation of monodisperse and uniform α-Ag₂WO₄ nanorods and nanowires using a facile precipitation approach. The key strategy of this approach is to allow (1) crystal growth to occur undisturbed and (2) sufficient time for equilibrium structures to be formed or to let nature take its course. The aspect ratio of the 1D products can be tuned by varying the duration of stirring during the initial reaction period. Analysis of the reaction intermediates revealed a three-stage growth mechanism involving the directed aggregation of spherical building blocks. The uniformity of the products can be attributed to self-focusing phenomena, in which sedimentation and the redistribution of mass yield 1D nanostructures with uniform lengths and diameters, respectively. α-Ag₂WO₄ nanowires and sub-micrometer rods were found to exhibit dissimilar absorption characteristics that led to the photodegradation of rhodamine B via different mechanisms.