Enhancement of Eu and Ce doped TiO₂ thin films photoactivity: Application on Amido Black photodegradation

Cerium (Ce) and Europium (Eu) doped TiO₂ thin films photocatalysts were synthesized using sol gel spin coating method coated on silicon wafers. SEM-EDX micrographs revealed that the surfaces were formed by compact grains and were covered by large aggregates. XRD and RAMAN analysis showed that the crystalline anatase TiO₂ is the dominant phase. The photoactivity of the films was investigated based on the degradation of Amido Black dye (AB), chosen as a model pollutant, under UV irradiation. Photodegradation of AB was investigated by varying the catalyst, initial solution pH and dye concentrations. Results showed that Eu-TiO₂ photocatalysts (0.1 wt%) exhibited the best enhancement of photoactivity performance in AB removal, reaching a reaction rate of 0.029 min⁻¹ and t_1/2 was around 25 min, under an optimal pH value of 3.5 and AB concentration of 10 ppm, which was faster than pure TiO₂ and Ce-TiO₂ films. The TiO₂ doping with Ce: 1 wt% or Eu: 0.1 wt% is corresponding to the optimal concentration for better electron/hole separation. EIS measurements conducted in alkaline medium proved that Ce-TiO₂(1 wt%) and Eu-TiO₂(0.1 wt%) photocatalysts possessed a lower electron transfer resistance than pure TiO₂, which can lead to an effective separation of photogenerated electron/hole pairs during the photodegradation reactions.