Integration of g-C3N4 into cellulose/graphene oxide foams for efficient photocatalytic Cr(VI) reduction

Abstract

Graphitic carbon nitride (g-C3N4) exhibits unique optical properties and it is regarded as an excellent photocatalyst. However, powdered g-C3N4 suffers from limited carrier mobility and poor recyclability. Here, g-C3N4 powders are integrated into cellulose/graphene oxide (GO) matrix to obtain a convenient and three-dimensional foam via a freeze-drying method. Owing to the formation of crosslinks between and g-C3N4 and carboxylic cellulose, the g-C3N4 particles attach tightly to the foam skeleton and are uniformly dispersed. As-prepared foams have good mechanical flexibility and superior water stability. Visible light driven reduction of Cr(VI) was utilized to evaluate the photocatalytic performance. The optimal sample (CG-3 with 60 wt% g-C3N4 loading) can reduce 98% of Cr(VI) within 3 h, even performs better than powdered g-C3N4 counterpart. The presence of GO facilitates the light absorption and promotes the stability of composite films. Moreover, the composite foams are facile to recycle without complex separation procedures. The CG-3 has no significant loss of its original reduction performance after 9 cycles, proving desirable reusability. This work provides a solution for powder catalyst recovery and inspires the materials design on g-C3N4.