Rational design of ZnFe2O4/g-C3N4 heterostructures composites for high efficient visible-light photocatalysis for degradation of aqueous organic pollutants

Abstract

A novel ZnFe2O4/g-C3N4 hybrid photocatalyst with different ratio was prepared by a facile and one step microwave irradiation method for the first time. Characterization results of XRD SEM, and TEM demonstrated that FCC spinel structural of ZnFe2O4 with monodispersed individual spherical shaped nanoparticles (sizes in the range of 35–45 nm) are wrapped on the surface of g-C3N4 nanosheets. The extent of absorption in the visible light region and effective prevent the electron-hole pair recombination was identified through UV–Vis-DRS and PL analysis. The visible light active ZnFe2O4/g-C3N4 heterostructure was used for the decomposition of methyl orange (MO) and rhodamine B (RhB) under stimulated visible light irradiation. ZnFe2O4/g-C3N4 composition, 15 wt.% (ZnFe2O4 loaded g-C3N4) composition has the highest rate of the degradation such as high removal efficiency (98%) and huge apparent constant (0.1955 min−1) and long term stability towards RhB. The kinetic constant over ZnFe2O4/g-C3N4 heterostructure photocatalyst was more than 15 times larger than that over pure ZnFe2O4 (0.0085 min−1). The photogenerated electrons from g-C3N4 surfaces could easily migrate to ZnFe2O4, leading to efficient separation of electron–hole pairs. The possible photocatalytic mechanism and photocatalytic activity enhanced mechanism has been proposed, taking into account the photosensitization effect and synergetic effect of ZnFe2O4 with g-C3N4.