g-C3N4/Bi4O5I2 2D-2D heterojunctional nanosheets with enhanced visible-light photocatalytic activity

We disclose the fabrication of 2D-2D heterojunctional nanosheets g-C3N4/Bi4O5I2 photocatalyst by using a mixed-calcination method. This synthetic method enables intimate interfacial interaction between g-C3N4 and Bi4O5I2, which is beneficial for charge transfer at the interface. The photocatalysis properties of g-C3N4/Bi4O5I2 composites were studied by photodegradation of Rhodamine B (RhB) and NO removal under visible-light (lambda > 420 nm) irradiation. The results revealed that the g-C3N4/Bi4O5I2 composites show enhanced photocatalytic activity compared to the pristine g-C3N4 and Bi4O5I2 samples. Investigations on the behaviours of charge carriers via photoluminescence (PL) spectra and transient photocurrent responses suggest that the g-C3N4/Bi4O5I2 heterostructure is responsible for the efficient separation and transfer of photogenerated electron-hole pairs, thus giving rise to the higher photocatalytic activity. The formation of 2D-2D heterostructured n-n type g-C3N4/Bi4O5I2 composites as well as photocatalytic mechanism was verified by a series of combined techniques, including the active species trapping experiments and Mott-Schottky plots. The present work furthered our understanding on fabrication of homogeneous heterojunction photocatalyst.