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

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.