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

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.