Peroxymonosulfate activation by iron oxide modified g-C3N4 under visible light for pollutants degradation

Graphitic carbon nitride (g-C 3 N 4 ) can be used as catalysts for peroxymonosulfate (PMS) activation and pollutants degradation under visible light irradiation. However, its efficiency is relative slow in comparison with copper and cobalt oxide catalysts. In this study, iron oxide modified g-C 3 N 4 catalysts (Fe 2 O 3 /g-C 3 N 4 ) were prepared by a simple thermal treatment method using urea and ferric nitrate as precursors. The materials were thoroughly characterized by a variety of techniques and their activity was evaluated for degradation of Acid orange 7 (AO7) and other dyes under visible light irradiation in the presence of PMS, with nearly complete degradation of all the pollutants obtained within 40   min. The prepared Fe 2 O 3 /g-C 3 N 4 catalysts were also proved more efficient than the single components and were stable during multiple runs. The enhanced photoactivity can be attributed to 1) the higher surface area, supplying more surface active sites and making charge carriers transport easier; 2) improved optical properties with narrower band-gap energies and increased visible light absorption efficiency, and 3) the participation of iron species in the reaction with production of more radicals. Thus, the low cost Fe 2 O 3 /g-C 3 N 4 composites with a facile synthesis process are very promising photocatalysts for PMS activation and pollutants degradation.