*2.2. Photocatalytic Performance Experiment*

The piezo/photocatalytic activities were evaluated by the degradation of RhB under UV–vis light irradiation and ultrasound. The 0.1 g catalyst was added into the RhB aqueous solution (100 mL, 5 mg/L) in dark and stirred for 30 min to reach adsorption–desorption equilibrium. After that, the mixed solution was treated with UV–vis light irradiation (300 W Xe lamp) and ultrasonic (50 W, 40 kHz). Change the water every five minutes to avoid the effects of temperature. A 4 mL solution was taken out every 20 min and centrifuged to remove the catalyst. The residual amount of RhB was recorded by the UV–vis spectrophotometer (Yoke, N6000, Shanghai, China) within the range of 300–800 nm.
