Solvent-Free Synthesis of Bismuth Oxychloride Microflower/Nanosheet Homojunctions for Photoactivity Enhancement

Graphical No wallflower ! BiOCl microflower/nanosheet homojunctions were constructed via a solvent-free route with enhanced photogenerated charge carrier separation and photoactivity. Solvent-free synthesis of bismuth-based photocatalysts with hierarchical architectures has been rarely reported yet. Herein, BiOCl hierarchical microflowers (MFs) were prepared via a solvent-free route for the first time, using chlorobutanol as the chlorine source. The reaction temperature ( T ) plays a key role for formation of MFs. The MFs were formed at T >120 °C and some MFs merged into large nanosheets (LNs). MF/LN homojunctions were constructed because considerable differences in sizes and exposed facets between the MFs and the LNs cause differences in their energy band levels. The sample prepared at 120 °C possesses the highest contents of MFs and homojunctions, specific surface area ( S BET , 13 m 2 g −1 ), and photoactivity, indicating the high photoactivity of the sample arises from fabrication of homojunctions as well as the high S BET . This work provides a solvent-free way to simultaneously synthesize BiOCl MFs and homojunctions, which paves an avenue for solvent-free synthesis of other photocatalysts.