In this study, we report the utilization of different water contents (0–40 vol.%) as cosolvent to ethaline, ChCl:EG (deep eutectic solvent) at the mole ratio of 1:2 to prepare binary oxide of tungsten oxide-molybdenum oxide nanocomposite in an ambient environment, followed by characterization using XRD, FTIR, SEM, TEM, TGA, XPS and UV–vis spectroscopy. The as-prepared composite composed of aggregated particles at low temperature of 60 °C, in the crystallite sizes ranging from ˜48.40 to 71.97 nm, with water cosolvent acting as bad solvent. Further characterizations revealed that the atomic percentage ratios of tungsten and molybdenum components increase with decrease in carbon content as the water content increases, while the morphology changes from cubic to prismatic polyhedral-like structures at low temperature, in addition to retaining ˜73% of its original weight above 700 °C. The UV–vis analysis revealed broad absorption at 239–374 nm with a threshold value of 527 nm and can attain maximum photochromic response in less 60 s on exposure to UV–vis light irradiation.
