Synthesis and application of CuO-TiO2 hybrid nanostructures as Photocatalytst for degradation of p-nitrophenol in wastewater

Abstract

The synthesis of CuO-TiO2 hybrid nanostructures using the sol–gel method, as well as their characterization as photocatalysts for photodegradation of p-nitrophenol (PNP) in industrial wastewater under sunlight irradiation, were presented in this paper. According to SEM and XRD investigations, the CuO-TiO2 hybrid nanostructure had a mixture of monoclinic structure CuO and anatase phase TiO2, indicating that the CuO-TiO2 hybrid nanostructure was successfully synthesised using the sol–gel method. Optical band gap values for CuO, TiO2, and CuO-TiO2 were determined to be 1.64, 3.02, and 2.10 eV, respectively. Electrochemical tests revealed that CuO-TiO2 has a longer electron lifetime, a higher separation efficiency, and a faster diffusion rate. After 75, 65, and 50 minutes of sunshine irradiation, full elimination of 200 mL of 10 mg/l PNP was obtained employing the photocatalytic activity of TiO2, CuO, and CuO-TiO2, respectively. These findings support CuO-high TiO2's photocatalytic activity when exposed to sunlight, owing to the synergistic effect of CuO and TiO2 in forming a CuO-TiO2 heterojunction with efficient separation of photo-generated electrons and holes, which improves electron transport. After 35, 90, and 150 minutes of UV irradiation, 100% treatment of 5, 30, and 100 mg/L of PNP was obtained, respectively. The CuO-practical TiO2's photocatalytic removal capacity was tested for degradation of a 200 mL 5 mg/L PNP solution generated from genuine industrial wastewater, demonstrating CuO-efficient TiO2's photocatalytic activity for PNP removal from real industrial wastewater.