Plastic optical fibres applied on the photocatalytic degradation of phenol with Ag₂MoO₄ and ß-Ag₂MoO₄/Ag₃PO₄ under visible light

ABSTRACT

In this study, plastic optical fibre (POF) was considered as a light-transmitting medium and substrate for use in a photocatalytic environmental purification system, using Ag₂MoO₄ and β-Ag₂MoO₄/Ag₃PO₄ as photocatalysts. Pure Ag₂MoO₄ and a β-Ag₂MoO₄/Ag₃PO₄ composite were synthesized using a facile precipitation method. The composition, structures and optical properties of as-prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), field-emission scanning electron microscopy (FESEM), UV/Vis diffuse reflectance spectroscopy (UV/Vis DRS), BET surface area and TGA/DTG. The catalysts were immobilized on POF and on the glass reactor surface and their efficiency in the phenol degradation was evaluated in a batch reactor under visible light. The use of POF offers advantages such as ease of handling and good adherence characteristics to support Ag₂MoO_4. The photoactivity follows the order β-Ag₂MoO₄/Ag₃PO₄ ≅ Ag₂MoO₄> TiO₂ P25, for photocatalysts immobilized on the glass reactor surface or in aqueous suspension. The immobilization of Ag₂MoO₄ on POF revealed that thinner Ag₂MoO₄ coatings achieved faster pollutant removal rates from solution, and the optimal catalyst deposition is 0.64 mg/cm², causing maximum the light penetration and electron–hole generation close to the solid–liquid interface.

GRAPHICAL ABSTRACT

KEYWORDS:

• Photocatalysis
• facile precipitation method
• metal-based molybdates
• immobilization of photocatalyst
• organic pollutants

Acknowledgements

The authors would like to thank the National Council for Scientific and Technological Development (CNPq) and the Coordination for the Improvement of Higher Level Personnel (CAPES) for their financial support. They also acknowledge the Central Laboratory of Electronic Microscopy (LCME-UFSC) for technical support.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico [grant number 405.223/2018-8; 301.479/2018-6] and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [grant number 88887.310560/2018-00].