Green synthesis of SiO₂ from Equisetnm arvense plant for synthesis of SiO₂/ZIF-8 MOF nanocomposite as photocatalyst

Abstract

Equisetnm arvense plant extract was used for preparing amorphous SiO₂. For preparing of SiO₂/zeolitic imidazolate framework-8 (ZIF-8) nanocomposite by solvothermal method, the synthesized SiO₂ was added to synthesis mixture ZIF-8. The photocatalytic activity of SiO₂/ZIF-8 was investigated systematically by degrading crystal violet as a cationic dye under UV light irradiation. The photodegradation of crystal violet by SiO₂, ZIF-8 and SiO₂/ZIF-8 samples was 13.7%, 25.6% and 75.6% during UV-light irradiation for 15 min. Among synthesized samples (SiO₂, ZIF-8 and SiO₂/ZIF-8), the SiO₂/ZIF-8 exhibited highest photocatalytic activity and improved stability compared to pure SiO₂ and ZIF-8. As evidenced from SEM and TEM images, ZIF-8 particles without aggregation located over SiO₂. The enhancement of the photocatalytic activity is due to the fact that the introduction of insulator SiO₂ in SiO₂/ZIF-8 composites can modify the surface state of the composite; more importantly, the energy level of SiO₂ can help accelerate the separation and transfer of electron-hole pairs of ZIF-8. The SiO₂/ZIF-8 photocatalyst did not show any obvious loss of photocatalytic activity during five cycles, which indicate that the heterostructured photocatalyst was stable and can be used repeatedly.

Keywords:

• Amorphous SiO₂
• zeolitic imidazolate framework-8
• aggregation
• crystal violet

Acknowledgements

The authors are grateful to the Islamic Azad University, Rasht Branch.

Disclosure statement

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