Constructing a novel ternary Fe(III)/graphene/g-C3N4 composite photocatalyst with enhanced visible-light driven photocatalytic activity via interfacial charge transfer effect

•The interfacial charge transfer effect (IFCT) was first introduced to g-C3N4 for improving its photocatalytic activity by grafting Fe(III) species on the surfaces of g-C3N4 via a simple impregnation method.•A novel ternary Fe(III)/graphene/g-C3N4 photocatalyst was successfully constructed by the combination of g-C3N4 with graphene along with the grafting of Fe(III) species on their surfaces.•The obtained 25%-Fe–GE–CN displayed enhanced photocatalytic activity (11.28 times of pristine g-C3N4) for photodegradation of MO under visible light irradiation.

Interfacial charge transfer effect (IFCT) was introduced into g-C3N4 by grafting Fe(III) species on its surface via a simple impregnation method. It has been shown that the obtained Fe(III)-grafted g-C3N4 photocatalyst exhibited enhanced visible-light absorption, reduced charge recombination and improved photocatalytic activity as compared with those of g-C3N4, due to the interfacial charge transfer between the Fe(III) species and g-C3N4. Furthermore, a novel ternary Fe(III)/graphene/g-C3N4 photocatalyst was successfully constructed by integrating graphene into the binary Fe(III)/g-C3N4 composite as the electron mediator. It has been found that the introduction of graphene made the Fe species show well distribution, smaller size and relatively high content in the ternary photocatalyst as compared with those in the binary one, revealing a synergistic effect between the Fe(III) species and graphene existed in the ternary photocatalyst. Consequently, the photocatalytic activity of the ternary Fe(III)/graphene/g-C3N4 photocatalyst was superior to that of the binary one, originating from its stronger visible-light absorption and more reduced charge combination. The ternary composite that consists of transition metal, graphene and g-C3N4 represents a new kind of high-efficiency visible-light-driven photocatalysts for water disinfection.

Graphical abstractSchematic illustration of hole–electron separation and transfer process for the 25%-Fe/GE/CN photocatalysts under visible light irradiation (>420 nm).Figure optionsDownload full-size imageDownload as PowerPoint slide