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 t1/2 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.