A promising Ag₂CrO₄/LaFeO₃ heterojunction photocatalyst applied to photo-Fenton degradation of RhB

ABSTRACT

Ag₂CrO₄ nanoparticles (10–35 nm) were assembled onto LaFeO₃ nanoparticles (20–60 nm) via a facile chemical precipitation method to form novel Ag₂CrO₄–LaFeO₃ heterojunction composite photocatalysts. The prepared Ag₂CrO₄–LaFeO₃ composites were characterized by XRD, SEM, TEM, XPS, BET, UV-vis DRS, PL spectroscopy and EIS and photocurrent response. The TEM result clearly shows that Ag₂CrO₄ particles are decorated onto LaFeO₃ particles to form Ag₂CrO₄–LaFeO₃ heterojunction. Compared to bare LaFeO₃, the 10%Ag₂CrO₄-LaFeO₃ composite exhibits a slightly increased BET specific surface area, increased photocurrent density, decreased charge-transfer resistance and decreased PL emission peaks. Using simulated sunlight as the light source and in the presence of H₂O₂, the photo-Fenton performance of the composite photocatalysts toward the degradation of RhB was investigated, revealing that they manifest significantly enhanced photo-Fenton degradation of RhB when compared with bare LaFeO₃ and Ag₂CrO₄. Among the composite photocatalysts, 10%Ag₂CrO₄–LaFeO₃ exhibits the highest photo-Fenton activity, which is about 3.1 and 2.5 times higher than that of bare LaFeO₃ and Ag₂CrO₄, respectively. This is attributed to the fact that the composite photocatalysts have highly efficient separation of photogenerated electron–hole pairs due to the formation of Ag₂CrO₄–LaFeO₃ heterojunctions. Active species trapping experiments and ·OH detection experiments were carried out, from which it is concluded that ·OH radicals are the dominant reactive species causing the dye degradation. A synergistic mechanism was proposed to elucidate the enhanced photo-Fenton activity of Ag₂CrO₄–LaFeO₃ heterojunction composites.

GRAPHICAL ABSTRACT

KEYWORDS:

• Ag₂CrO₄-LaFeO₃ heterojunction
• photo-Fenton performance
• dye degradation
• synergistic effect

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51662027].