A comparative study of the effects of phase composition on optical properties and photocatalytic activity of α-/β-/γ-Bi₂O₃ multi-heterojunction prepared by submerged DC electrical arc discharge

ABSTRACT

α-/β-/γ-Bi₂O₃ photocatalytic nanocomposite was prepared through thermal treatment of synthesised nanoparticles by submerged arc discharge . FE-SEM reveals the formation of flake nanostructures after thermal treatment. The signatures of multi-heterojunction formation among α-, β- and γ-Bi₂O₃ are confirmed by the XRD and PL spectroscopy. The optical transmission spectra indicated narrower band gap of α-/β-/γ-Bi₂O₃ nanocomposites. The photocatalytic performance of the samples studied by degradation of methyl orange (MeO) and compared based on multi-heterojunction formation . The composite nanostructures exhibited about twice as high photocatalytic activity than single-phase nanostructures. Cyclic photocatalytic degradation reveal stable performance of α-/β-/γ-Bi₂O₃ nanocomposites for the long term and cyclic utilisation. The enhanced photocatalytic activity can be attribute to the formation of heterojunctions between α-, β- and γ-Bi₂O₃. . In addition, PL spectra indicated that the recombination rate of samples after thermal treatment are much lower than that of samples before thermal treatment.

KEYWORDS:

• Α-/β-/γ-Bi₂O₃
• multi-heterojunction
• photocatalytic activity
• electrical arc discharge
• thermal treatment
• optical properties

Acknowledgments

The authors would like to acknowledge the financial support received from Tarbait Modares University, through grant #IG-39703.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Tarbiat Modares University [IG-39703].