Preparation of La2Ti2O7/TiO2/Fe3O4 for effective persulfate activation under simulated sunlight irradiation

In this study, TiO2 nanosheets are employed as a template to prepare La2Ti2O7/TiO2 (TL), which is further modified by Fe3O4 to form a ternary catalyst La2Ti2O7/TiO2/Fe3O4 (TLF). The as-synthesized composite is confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis DRS spectra. According to the catalytic employment of TLF for the activation of persulfate (PS) in assistance of simulated sunlight, it is shown that TLF/PS/light system is able to degrade 93.7% tetracycline hydrochloride, giving 79.8% chemical oxygen demand (COD) removal in assistance of simulated solar light, both of which are apparently greater than that of La2Ti2O7/TiO2 and Fe3O4. The highly improved degradation efficiency can be ascribed to the fact the photo-induced electrons greatly accelerate the redox cycle of Fe(III)/Fe(II) during the PS activation. Besides, the heterojunction constructed between La2Ti2O7 and TiO2 that significantly suppresses the recombination of photo-excited carriers also contributes to the ameliorated catalytic performance.

Automated summary

This study utilized TiO2 nanosheets as a template to prepare a ternary catalyst TLF, which showed significantly improved catalytic performance in the activation of persulfate under simulated sunlight. The results demonstrated that the TLF/PS/light system could effectively degrade tetracycline hydrochloride and remove chemical oxygen demand, attributing the enhanced degradation efficiency to the acceleration of the redox cycle of Fe(III)/Fe(II) and the suppression of carrier recombination by the heterojunction structure between La2Ti2O7 and TiO2.