N-doped nanoporous graphene decorated three-dimensional CuO nanowire network and its application to photocatalytic degradation of dyes

Abstract

In this study, a three-dimensional CuO nanowire (NW) network decorated with N-doped graphene (NG/CuO) was fabricated by a method of thermal oxidation combined with hydrothermal and ion implantation. The morphological investigation of products was analyzed by field emission scanning electron microscopy (FESEM), which confirmed that the synthesized CuO is wire-shaped and obtained in a high density and large quantity. Meanwhile, it is found that the graphene was successfully wrapped on the surface of the CuO NWs. Subsequently, N ions were injected into graphene by using a plasma method. The detailed structural, compositional and optical characterizations of the synthesized NG/CuO are characterized by X-ray diffraction (XRD) patterns, transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) which have collectively confirmed that the obtained sample is highly crystalline CuO NWs decorated with N doped graphene. It is found that NG/CuO demonstrates better photocatalytic activity than the pristine graphene decorated CuO NW (Gra/CuO) and much higher activity than that of the pure CuO NW, which shows a good reproducibility and could be further enhanced by adding H₂O₂. The formation of a heterojunction between the N-doped graphene and CuO can efficiently avoid the combination of photogenerated carriers, which contributes to the enhancement of its photocatalytic activities.