Synergistic enhancement of visible light Photocatalysis: Tailoring dual Z-scheme Fe2O3/C3N4/NH2-MIL-125 ternary composites for organic pollutant degradation

Abstract

In this study, Fe2O3/C3N4/NH2-MIL-125 ternary composite photocatalysts were synthesized. Their amino groups provided close bonding between these materials, facilitating the effective separation of electrons and holes. Besides, each component of Fe2O3/C3N4/NH2-MIL-125 plays a crucial role. NH2-MIL-125 provided a high surface area, C3N4 contributed to the primary photocatalytic activity, and Fe2O3 aided in enhancing light absorption, generating additional potential to produce hydroxyl radicals, thereby further enhancing photocatalytic activity. Moreover, the proportion of loaded Fe2O3 and C3N4 in the ternary material was investigated. It was found that Fe2O3/C3N4/NH2-MIL-125 with a 1:1 ratio of Fe2O3 and C3N4 (FeCN1:1/NM125) exhibited excellent photocatalytic performance, in which RhB degradation reached 100% under visible light irradiation, conforming to first-order kinetics analysis with a reaction rate constant k of 0.0164 min−1. Its efficiency was twice that of the binary catalyst C3N4/NH2-MIL-125 or Fe2O3/NH2-MIL-125, seven times that of the pristine catalyst C3N4, and ten times that of the pristine catalyst NH2-MIL-125. Scavenger experiments showed that the degradation efficiencies were 52.57%, 55.51%, and 63.41%, respectively, indicating that three active species, namely superoxide radicals, holes, and hydroxyl radicals, made significant contributions to photocatalysis.