Hierarchical BiOI and hollow Bi_2WO_6 microspheres: Topochemical conversion and photocatalytic activities

摘要

We present here a facile one-pot surfactant-free solvothermal route to synthesize hierarchical BiOI microspheres assembled from nanosheets at 120 ℃ for 16 h. The as-synthesized BiOI microspheres could be topochemically converted into hollow hierarchical Bi_2WO_6 ones built by nanoplates for the first time under hydrothermal condition because of the analogies of crystal structures. The transformation process of hierarchical BiOI microspheres to hollow Bi_2WO_6 ones was surveyed through XRD analyses and FE-SEM observations of the intermediates at different reaction stages. Rhodamine B (RhB) was selected as pollutant model and visible-light-driven photocatalytic activities of hierarchical BiOI and Bi_2WO_6 microspheres under the same measurement conditions were comparatively studied. As a result, the photocatalytic activities of BiOI obviously outshone Bi_2WO_6. The present study not only develops a new method for fabricating hierarchical architectures but also provides some useful information on relative visible-light-responding photocatalytic activity of hierarchical BiOI and Bi_2WO_6 microspheres.