An efficient electrostatic self-assembly of reduced graphene oxide-BiOI/Bi 2 O 2 CO 3 p–n junction nanocomposites for enhanced visible-light photocatalytic activity

The BiOI/Bi2O2CO3 p–n junctions were constructed by anion exchange method with Bi2O2CO3 in situ growth on BiOI. Then, the surfaces of BiOI/Bi2O2CO3 samples were modified by negative charge with (3-aminopropyl) triethoxysilane (APTES) in an ethanol solution. Finally, the ami-BiOI/Bi2O2CO3/graphene (RGO) ternary composites were fabricates by the simple hydrothermal reaction. The obtained photocatalysts were well characterized with the various characterization techniques to study their morphological, physical, optical, and photocurrent properties, and have been evaluated by investigating the degradation of Rhodamine B and tetracycline under visible irradiation. Compared with single BiOI, the BiOI/Bi2O2CO3 photocatalysts displays higher photocatalytic activity, due to the formation of the electric fields between p–n heterojunction to promote the migration of photogenerated carriers. Moreover, the ami-BiOI/Bi2O2CO3/RGO composites with the best photocatalytic activities can be attributed to that the positively charged ami-BiOI/Bi2O2CO3 were coupled with the negatively charged graphite oxide (GO) by electrostatically attraction to form the effectively interfacial contacts, causing the photocatalytic reaction sites increased, the range of light response expanded, the separation of photogenerated charge further improved. This work provides a feasible strategy for the construction of high efficiency semiconductor and RGO nanocomposite photocatalyst.