Peroxymonosulfate-activated degradation of rhodamine B over one-dimensional H2Ti3O7/TiO2 heterostructures: synergistic effects and the reaction mechanism

Abstract

In this study, TiO₂ and anhydrous Na₂CO₃ were used as precursor materials to investigate the optimal conditions for synthesizing sodium titanate (Na₂Ti₃O₇) by the molten salt method. The sodium titanate reactant was acid-exchanged to prepare titanic acid (H₂Ti₃O₇), which was then calcined at different temperatures for varying durations. The resulting product was characterized by XRD, SEM, TEM, FE-SEM, and FTIR, confirming the formation of an H₂Ti₃O₇/TiO₂ composite. The photocatalytic degradation performance, mechanism, and stability of the H₂Ti₃O₇/TiO₂ composite were evaluated using rhodamine B as a model pollutant. The results indicated that the composite calcined at 800 °C for 3 h exhibited the fastest degradation rate. After the addition of peroxymonosulfate, the degradation efficiency reached approximately 100% within 30 min, which was higher than those of pure H₂Ti₃O₇ and TiO₂. The composite retained 94.56% of its original efficiency after four cycles, indicating excellent catalytic degradation ability. Quenching experiments revealed that the main active species were SO₄˙⁻, ˙O₂⁻, and ˙OH, and a possible degradation mechanism was proposed.