Ease synthesis of mesoporous WO3-TiO2 nanocomposites with enhanced photocatalytic performance for photodegradation of herbicide imazapyr under visible light and UV illumination.

Abstract Herein, we report the ease synthesis of mesoporous WO 3 –TiO 2 nanocomposites at different WO 3 contents (0–5 wt%) together with their photocatalytic performance for the degradation of the imazapyr herbicide under visible light and UV illumination. XRD and Raman spectra indicated that the highly crystalline anatase TiO 2 phase and monoclinic and triclinic of WO 3 were formed. The mesoporous TiO 2 exhibits large pore volumes of 0.267 cm 3  g−1 and high surface areas of 180 m 2  g −1 but they become reduced to 0.221 cm 3  g −1 and 113 m 2  g −1 , respectively upon WO 3 incorporation, with tunable mesopore diameter in the range of 5–6.5 nm. TEM images show WO 3 –TiO 2 nanocomposites are quite uniform with 10–15 nm of TiO 2 and 5–10 nm of WO 3 sizes. Under UV illumination, the overall photocatalytic efficiency of the 3% WO 3 –TiO 2 nanocomposite is 3.5 and 6.6 times higher than that of mesoporous TiO 2 and commercial UV-100 photocatalyst, respectively. The 3% WO 3 –TiO 2 nanocomposite is considered to be the optimum photocatalyst which is able to degrade completely (100% conversion) of imazapyr herbicide along 120 min with high photonic efficiency ∼8%. While under visible light illumination, the 0.5% WO 3 –TiO 2 nanocomposite is the optimum photocatalyst which achieves 46% photocatalytic efficiency.