Characterisation of binary (NiO)_x (Ag₂O)_1−x nanoparticles synthesised via the thermal treatment route

In this study, binary nickel oxide silver oxide nanoparticles (NiO)_x (Ag₂O)_1−x (NPs) were synthesised for the first time using the thermal treatment route at higher and lower precursor values. Two precursors and 5 g of polyvinyl pyrrolidone (PVP) were employed to obtain the (NiO)_x (Ag₂O)_1−x NPs at 700 °C. The obtained NiO NPs documented cubic and hexagonal phases when assessed with X-ray diffraction (XRD) at (x = 0.4 and 0.6) and (x = 0.2 and 0.8), respectively. The cubic phase was confirmed for Ag₂O NPs in all prepared samples. The smallest crystallite and particle sizes were found at x = 0.8. The particle size ranged from 23.0 to 45.0 nm, which was evaluated with a transmission electron microscope (TEM). Two shapes, NiO doped with porous Ag₂O nanosheets, were observed with a scanning electron microscope (SEM). The purity of the products was evaluated via energy-dispersive X-ray (EDX) spectroscopy. The synthesised NPs were composed of nickel (Ni), silver (Ag), and oxygen (O). Moreover, the X-ray photoelectron spectroscopy (XPS) analysis performed during this study revealed the chemical states of the Ni, Ag, and O present, which confirmed the purity of the NPs. The ultraviolet–visible spectroscopy (UV–Vis) assessment conducted also demonstrated that the energy band gaps for nickel oxide (NiO) and silver oxide (Ag₂O) increased with rising x values. The photoluminescence (PL) analysis performed in this study also verified the existence of two emission peaks attributable to NiO and Ag₂O, indicating that the NPs possess good photocatalytic activity. Consequently, the NPs synthesised in the present study could be applied as antimicrobial agents in wastewater treatment.