Effect of nanographene platelets on adsorption and sonophotocatalytic performances of TiO2/CuO composite for removal of organic pollutants

Highlights: • TiO₂/CuO composite incorporated with nanographene platelets (NGP). • Catalytic ability of TiO₂/CuO/NGP composite for removal of MB investigated. • Better adsorption ability for MB compared to TiO₂/CuO composite without NGP. • Adsorption ability increases with increasing NGP content up to optimal level. • TiO₂/CuO/NGP with 10 wt% NGP exhibits best photo- and sonophoto-catalysis. - Abstract: TiO₂/CuO composites incorporated with different amounts of nanographene platelets (NGP) were synthesized by hydrothermal processing. The TiO₂/CuO/NGP composite was characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, dynamical light scattering, Raman spectroscopy, Fourier–transform infrared spectroscopy, ultraviolet (UV)-visible diffuse reflectance spectroscopy, Brunauer—Emmett—Teller (BET) surface area analysis, and electron spin resonance. The catalytic ability of the composite for the removal of methylene blue from an aqueous solution was examined by adsorption, photocatalytic, and sonophotocatalytic experiments. The composite was found to exhibit better adsorption ability for methylene blue compared to the TiO₂/CuO composite without NGP. The photocatalytic activity of the composite was examined by UV and visible (Vis) light irradiation, while the sonophotocatalytic activity was examined by a combination of UV and Ultrasound (UV + US) and Vis + US. Both examinations showed that the light and ultrasonic responses were enhanced by compositing with NGP.