Photocatalysis and Piezoelectric Catalysis Synergy in Degradation of Methylene Blue Using a BaTiO3 Catalyst

The polyacrylamide gel method (PGM) was applied to synthesize pure BaTiO3 by using tetrabutyl titanate as the titanium source and adding NaOH to the precursor solution. A systematic investigation was performed to analyze the impact of the titanium source, acid, base, and sintering temperature on the purity of the BaTiO3 phase. Using a PGM with NaOH in the precursor solution, tetrabutyl titanate as the titanium source, and a sintering temperature of 950°C is an effective way to obtain pure BaTiO3. The BaTiO3 exhibits high catalytic activity for the degradation of methylene blue (MB) dye under vibration and light irradiation conditions in situ, with or without the addition of 2 mL of H2O2. The catalytic experiments proved that the optimal catalyst content, dye concentration, cycle index and H2O2 concentration of the BaTiO3 for the degradation of MB dye were 1.5 g/L, 10 mg/L, 4 and 2 mL, respectively. Under the conditions of ultrasound + light + O2, BaTiO3 produced hydrogen peroxide with a concentration of 1135 μmol/g in 180 min, providing conditions for the in-situ generation of hydrogen peroxide and the degradation of MB dye. According to in-situ experiments, BaTiO3 can degrade MB dye completely within 90 min. A mechanism that combines vibration catalysis and photocatalysis was proposed based on numerous experiments and theoretical discussions. The technical reference provided by this experimental idea can be used by other catalysts to generate hydrogen peroxide in-situ and degrade organic dyes.