Influence of ammonia on properties of TiO₂-MgFe₂O₄ as high visible-light active photocatalysts for the degradation of Rhodamine B

The influence of ammonia on TiO₂-MgFe₂O₄ catalysts synthesized via a hydrolysis and co-precipitation, followed by calcination at 500℃, was studied. Two different catalysts, TiO₂-MgFe₂O₄ (Am) and TiO₂-MgFe₂O₄ (W), were prepared using Ti-precursors, which were synthesized by the hydrolysis of Ti-butoxide with and without ammonia. The resulting TiO₂-MgFe₂O₄ catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), specific surface area measurements, X-ray diffraction, and UV-vis diffuse reflectance techniques. It was revealed that strong electronic coupling exists between the TiO₂ and MgFe₂O₄ components within the TiO₂-MgFe₂O₄ catalysts. Photocatalytic activity toward Rhodamine B (RhB) was investigated in aqueous solution under visible light irradiation. TiO₂-MgFe₂O₄ (W) was found to be an effective catalyst and had several advantages over TiO₂-MgFe₂O₄ (Am). These results clearly highlight that ammonia had a significant influence on the photocatalytic activity of the TiO₂-MgFe₂O₄ catalysts. Therefore, the results reported herein indicate that TiO2-MgFe₂O₄ is a green, low-cost, and highly efficient photocatalyst for environmental remediation. (author)