Recent Developments in Applications of G-CuO Nanocomposites for Photocatalytic Dye Removal

Abstract The extensive application of synthetic dyes across industries poses significant environmental challenges, particularly concerning water quality degradation. Regarding the possible solutions, copper oxide (CuO) stands out as a feasible candidate. Being a p-type Nano-heterogeneous semiconductor with a bandgap of 1.2–2.71 eV, CuO is a reasonable choice and widely studied photocatalyst for addressing such challenges. When the wavelength exceeded the UV-visible region, its functionality showed deterioration. At the same time, there are difficulties associated with reproducibility and reusability, as well as rapid electron-hole recombination, which prevent the widespread application of this technology within this spectral range. In an attempt to eliminate this defect, researchers have been investigating strategies to activate CuO under visible light, with one promising approach being carbon nanomaterials such as graphene to form carbon-CuO composites. The unique properties of graphene, i.e., its large surface area and excellent electron mobility, make it a remarkable candidate for the enhancement of CuO photoactivity. This study highlighted the recent progress in the synthesis of graphene-based CuO photocatalysts, with the main characteristic of extending the light absorption capacity of CuO into the visible spectrum. It reveals achievements in material innovations and applications, with a focus on photocatalytic dye degradation. These breakthroughs are a sign that the field is growing in popularity and is evolving.