Efficient Piezoelectric Catalytic Performance and Innovative Construction of BaTiO3/Zn2TiO4/ZnO Composite

A novel BaTiO 3 /Zn 2 TiO 4 /ZnO heterojunction composite was successfully synthesized via the molten salt method, and its piezoelectric catalytic performance for pollution degradation was evaluated with methyl orange (MO) as the target pollutant. After calcination at 900 °C for 3 h, the optimal sample demonstrated exceptional catalytic activity, with a MO degradation rate of up to 98.78%. Notably, even after four consecutive cycles, this catalyst maintained a degradation efficiency exceeding 85%, indicating favorable stability and reusability. Radical trapping experiments were carried out to explore the degradation mechanism, showing that silver nitrate (AgNO 3 ) significantly enhanced the degradation efficiency over time, while disodium ethylenediaminetetraacetate (EDTA-2Na), methanol (CH 3 OH), and tert-butyl alcohol (TBA) inhibited the reaction to varying degrees. The superior catalytic activity of the BaTiO 3 /Zn 2 TiO 4 /ZnO system is mainly attributed to the strong synergistic effect between its piezoelectric catalytic performance and peroxymonosulfate (PMS). During the piezoelectric activation of PMS for MO degradation, hydroxyl radicals (·OH), sulfate radicals (SO 4 −·), and superoxide anions (O 2 −·) serve as the main reactive oxygen species, playing a dominant role in the reaction. These findings further elucidate the piezoelectric catalytic mechanism of the BaTiO 3 /Zn 2 TiO 4 /ZnO system in MO degradation. Graphical The BaTiO 3 /Zn 2 TiO 4 /ZnO catalyst, under ultrasonic irradiation, synergistically activates peroxymonosulfate (PMS) and ambient oxygen. This process yields a suite of reactive species, including sulfate (SO 4 · − ) and hydroxyl (·OH) radicals, as well as superoxide anion radicals (·O 2 − ), which collectively degrade methyl orange (MO), resulting in the complete mineralization to CO 2 and H 2 O.