Enhanced CO₂ photo-reduction under visible light irradiation by rGO incorporated Cu₂O nanocomposite

In this study, cuprous oxide (Cu 2 O) was employed as a photocatalyst for reduction reactions under visible light. To enhance its photocatalytic activity, varying proportions of reduced graphene oxide (rGO) were incorporated, and the reduction performance was evaluated under different light sources to determine the yields of CH₄ and CO. X-ray diffraction (XRD) confirmed the successful synthesis of Cu₂O, while transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to characterize the material’s morphology, composition, and valence band position. The photocatalytic reactions were conducted using 15W green, blue, and red light-emitting diodes (LEDs) as light sources. Water vapor, generated from a water container, was introduced into the reaction chamber to interact with the photocatalyst. The resulting CH 4 and CO yields were quantified using gas chromatography (GC). Under red, green, and blue light irradiation, the methane yields were 24.24 μmol g -1 , 21.82 μmol g -1 , and 20.59 μmol g -1 , respectively, while the cumulative CO yields were 26.05 μmol g -1 , 25.76 μmol g -1 , and 24.65 μmol g -1 , respectively. For the 2:1 Cu 2 O:rGO composite, the quantum yields were 0.30%, 0.22%, and 0.18% for CH 4 and 0.08%, 0.06%, and 0.05% for CO under red, green, and blue light, respectively.