Enhancing the photocatalytic activity of Ga 2 O 3 –TiO 2 nanocomposites using sonication amplitudes for the degradation of Rhodamine B dye

A Ga 2 O 3 –TiO 2 photocatalyst was synthesized by a mechanomixing method followed by a sonication technique using different amplitudes of sonication (0%, 25%, 50%, and 75% of 20 kHz). The prepared photocatalysts were characterized by X‐ray diffraction, X‐ray photoelectron spectroscopy, Fourier‐transform infrared, Brunauer–Emmett–Teller (BET) surface area ( S BET ), zeta potential, and optical techniques. Ga 2 O 3 –TiO 2 exhibited an excellent photocatalytic activity for Rhodamine B (RhB) dye degradation under UV irradiation. The RhB degradation rate rose linearly with the increase of sonication amplitude. The photodegradation rate ( k ) of the synthesized samples was calculated according to the Langmuir–Hinshelwood kinetic expression. It reached a maximum of 5.25 × 10 −2 min −1 with R 2 of 0.99 for Ga 2 O 3 –TiO 2 (75%) photocatalysts. The main reactive species were detected through radical scavenging experiments. The formation of hole reactive species is the rate‐determining step in the case of Ga 2 O 3 –TiO 2 (75%) photocatalysts.