Plasmonic Silver (Ag) Supported Mesoporous CuO Nanocomposites for Photodegradation of Methylene Blue in Water

Abstract Water decontamination remains a challenge in many developing and developed countries. And thus, efficient and affordable approaches are urgently needed. In this research work, a heterogeneous photocatalyst of Ag@CuO nanocomposites (NCs) has been successfully biogenic synthesized using Cactus pears extracts for the decomposition of methylene blue (MB) under visible light irradiation. The obtained nanocomposites consisted of plasmonic silver (Ag) NPs embedded in a semiconductor matrix of copper oxide (CuO). The scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and Rutherford backscattering spectrometry (RBS) were employed to characterize the morphology, and microstructures of the samples. The SEM images of Ag@CuO NCs confirm the presence of better dispersibility of Ag nanoparticles (NPs) in the nanorod-like surface of CuO. XRD patterns revealed a well-crystalline nature of monoclinic phase of CuO and face centered cubic (fcc) of Ag metal, and EDX spectra confirms the compositions of the nanocomposites. The FT-IR confirmed the secondary metabolites in Cactus pears for the formation of Ag NPs, and Ag@CuO NCs. The Brunauer-Emmett-Teller (BET) surface area of CuO NPs, and Ag@CuO NCs were achieved from N 2 adsorption/desorption isotherm and revealed a specific area of 8.67 m 2 g −1 and 15.14 m 2 g −1 , respectively with a mesoporous nature. The heterogeneous biogenic Ag@CuO NCs was evaluated for the photocatalytic degradation of methylene blue (MB) dye upon light irradiation and demonstrated higher degradation kinetics rate (k = 0.0578 min −1 ) compared to CuO (k = 0.0362 min −1 ). The superior photocatalysis activity of Ag@CuO NCs is ascribed to the synergistic effects of enhanced light absorption, higher adsorption capacity, improved charge-separation and high surface area. Graphical Abstract