Nanoscale p-n heterojunctions of BiOI/nitrogen-doped reduced graphene oxide as a high performance photocatalyst

Bismuth oxygen iodine (BiOI) is an emerging visible-light photocatalyst for water purification and contamination treatment. However, the performance of bare BiOI is restricted by the short lifetime of photogenerated electron-hole pairs. Herein, nitrogen-doped reduced graphene oxide (rGO) flakes self-assemble on the spherical superstructures of BiOI nanoplates via solvothermal reactions. The products are nanoscale p-BiOI/n-rGO heterojunctions with highly efficient visible light photocatalytic degradation activities. Optimum photocatalytic efficiency is obtained with ∼2.83% weight ratio of loaded n-rGO, and the activity increased by 2.1 times for removal of phenol and 1.8 times for degradation of rhodamine B over with bare BiOI. Experimental measurements demonstrate that the enhanced photocatalytic performance of p-BiOI/n-rGO is ascribed to the improvement in all three vital steps in photocatalysis: charge separation, migration, and recombination, which benefit from the built-in electric field of the nanoscale p-BiOI/n-rGO heterojunctions. Our method provides a cost-effective solution for high-efficiency visible-light-response photocatalyst.