Ultrasound assisted synthesis of TiO2–WO3 heterostructures for the catalytic degradation of Tergitol (NP-9) in water

• TiO2–WO3 heterostructures were synthesized at room temperature via a sonochemical approach.
• TEM and EDX images show that the prepared TiO2–WO3 heterostructures consists of globular agglomerates.
• TiO2–WO3 heterostructures were used for the degradation of wastewater pollutant containing Tergitol with ozonation.

TiO2–WO3 heterostructures were synthesized at room temperature, ambient pressure, and short reaction time via a sonochemical approach. TEM and EDX images show that the prepared TiO2–WO3 heterostructures consist of globular agglomerates (∼250 nm in diameter) composed of very small (<5 nm) dense particles (WO3) dispersed inside the globules. The observed less intense monoclinic WO3 diffraction peak (around 2θ = 22° belonging to (0 0 1) plane) and the high intense hexagonal WO3 diffraction peak (around 2θ = 28° belonging to (2 0 0) plane) in XRD indicate that there may be phase transition occurring due to the formation of intimate bond between TiO2 and WO3. In addition, the formation of such new phase was also observed from Raman spectra with a new peak at 955 cm−1, which is due to the symmetric stretching of W = O terminal. The catalytic activity of TiO2–WO3 heterostructures was tested for the degradation of wastewater pollutant containing Tergitol (NP-9) by a process combined with ozonation and it showed two-fold degradation rate compared with ozone process alone.