One pot controllable synthesis of palygorskite/bismuth oxyiodide hierarchical microspheres for improved visible-light photocatalytic performance

Development of semiconductor heterojunction with hierarchical architectures is highly effectual for boosting photocatalytic performance. In this work, two kinds of assembled 3D palygorskite/bismuth oxyiodide (Pal/BixOyIz) composites with natural palygorskite intercalated into the microspheres, namely Pal/Bi5O7I/Bi4O5I2 and Pal/Bi5O7I, were constructed via a facile one step calcination strategy using different Pal/BiOI composites as precursors. The results demonstrated that the content of 1D palygorskite nanofibers played a vital role in the process, which influenced both the morphologies and the thermal-treated products. The photocatalytic behavior of the obtained samples was surveyed by decomposition of Rhodamine B (RhB) and tetracycline hydrochloride (TCH) under visible light irradiation (lambda > 420 nm), in which Pal/Bi5O7I/Bi4O5I2 microspheres composites manifested optimal photocatalytic performance. This activity enhancement was mainly attributed to the enlarged specific surface area with the intercalation of palygorskite, increased density of photogenerated carriers and more efficient charge separation and migration owing to the formation of type II heterojunction. This study supplies an effective way to obtain promising 3D microstructure for high-efficiency visible-light-driven pollutants degradation.