A novel FeS2@g-C3N4 composite with enhanced photo-Fenton catalytic activity for pollutant degradation

Abstract

As a metal-free photocatalyst, graphitic carbon nitride (g-C3N4) has been widely used in organic pollutant degradation. However, its photocatalytic efficiency is restricted by its low absorbance of visible light and rapid electron-hole recombination rate. To enhance the catalytic activity in pollutant degradation, a hybrid photo-Fenton catalyst was prepared by coupling FeS2 with g-C3N4 via a simple hydrothermal method. Consequently, a huge enhancement in degradation efficiency was observed as the model molecule (RhB) can be completely degraded in 60 min in the presence of 5 mM H2O2 under visible light irradiation. Furthermore, the catalyst shows a high stability and degradation efficiency even after 5 consecutive runs. The mechanism investigations reveal: (1) the heterostructure between FeS2 and g-C3N4 can shorten the band gap and accelerate the separation and transportation of photoexcited charge carriers; (2) the formation of the heterostructure can not only boosts Fe2+ catalyzed ·OH production via H2O2, but also increases the formation of ·O2− from O2; (3) the generated ·OH and ·O2− as well as the photoinduced holes have all contributed to the improvement of degradation efficiency. Thus present work provides a promising way of building a highly efficient photo-Fenton catalyst that is applicable in purification of wastewater.