Cu₂O-CuO@biochar composite: Synthesis, characterization and its efficient photocatalytic performance

This research focuses on the facile hydrothermal preparation of Cu₂O-CuO@biochar (Cu₂O-CuO@BC) composites of different BC content (0.5, 1.0, and 2.0 g/L) as efficient photocatalysts for the decomposition and mineralization of Reactive Orange 29 (RO29). The textural and morphological properties of biochar-based composites were studied utilizing BET, TEM, and SEM analyses. Moreover, EDX, XRD, UV–Vis, DRS and FTIR characterization was carried out to evaluate the elemental composition, crystalline structure, optical characteristics and functional groups of the samples, respectively. The Cu₂[email protected] composite with a BC content of 1.0 g/L exhibited superior photocatalytic performance than the individual counterparts BC and Cu₂O-CuO, due to its narrow band gap and high surface area. These characteristics led to the synergetic ability of UV irradiation and photocatalytic performance of Cu₂O-CuO@BC to generate oxidizing species and subsequent radical reactions. The generation of some by-products was verified using GC–MS analysis and accordingly, a possible pathway was proposed. 94.12% degradation efficiency of RO29 was obtained by Cu₂[email protected] composite at the natural pH of RO29 solution (8.9) and initial RO29 concentration of 20 mg/L after 90 min of photocatalysis. Under identical conditions, 47.31% and 79.62% COD removal efficiencies were observed after 90 and 180 min treatment, respectively.