Impact of graphene oxide on visible light photocatalytic performance of graphene oxide/graphitic carbon nitride three-dimensional structure composites.

The non-metallic catalyst graphitic carbon nitride (g-CN) has attracted a significant amount of attention due to its excellent photocatalytic performance. The photocatalytic performance of g-CN has been further enhanced by the incorporation of graphene oxide (GO) as a composite catalyst. However, the enrichment and recovery of these two-dimensional composites after photocatalysis is still a difficult challenge. In this work, a visible light responsive graphene oxide/graphitic carbon nitride coated sponge three-dimensional composite (PU-GO/g-CN) was prepared by electrostatic self-assembly using polyurethane sponge (PU) as a skeleton and g-CN as a photocatalyst. The degradation rate of rhodamine B (RhB) under visible light was used as an index to evaluate the photocatalytic performance of PU-GO/g-CN. The results demonstrate that during the photocatalytic degradation of RhB by PU-GO/g-CN, g-CN is the main photocatalyst, while the holes and the superoxide radicals generated by electron excitation are the main agents. As a bridge connecting PU and g-CN, GO improves the agglomeration phenomenon of g-CN on PU. Meanwhile, GO has excellent carrier mobility and inhibits the recombination of photogenerated electrons and holes. Moreover, the presence of GO enhances the absorption of light and dyes. Overall, the addition of GO effectively enhances the photocatalytic performance of PU-GO/g-CN due to it enhances dye absorption, improves light energy utilization rate, and expedites transfer of photogenerated electrons. After 5 cycles, PU-GO/g-CN still exhibits an RhB degradation rate of 92.06%, demonstrating good stability and recycling performance. This material shows great promise for practical environmental remediation applications.