Cerium and europium doped TiO2 thin films deposited by a sol-gel dip-coating process: characterization and photocatalytic activity toward dye degradation

Abstract

Cerium (Ce) and europium (Eu)-doped TiO 2 thin films were obtained by sol-gel dip-coating technique. SEM micrographs showed that the surfaces are covered by agglomerated particles due to the repeating coating process. XRD patterns showed the presence of TiO 2 anatase phase. Raman spectra revealed that the peaks recorded at 146 cm −1 (E g ) and 397 cm −1 (B 1g ) were related to the anatase phase. EIS measurements proved that Ce-TiO 2 (1wt%) and Eu-TiO 2 (0.1wt%) photocatalysts possessed a lower electron transfer resistance than pure TiO 2 , which can lead to effective separation of electron/ hole pairs during the photoreactions. The photoactivity of Ce and Eu-doped TiO 2 was investigated by the degradation of amido black10B dye (AB) under UV excitation and varying the initial pH and concentrations. It was found that Eu-TiO 2 (0.1wt%) exhibited higher photocatalytic activity, reaching a first-order reaction rate of k app (0.036min −1 ), t 1/2 was around 12 min and AB removal was 98.94%, under optimal pH of 3.5 and AB concentration of 10ppm compared to (t 1/2 = 45 min, t 1/2 =30 min), ( k app = 0.022 min −1 , k app =0.026min −1 ) and AB removal (94.78%, 96.44%), respectively for pure TiO 2 and Ce-TiO 2 (1wt%). Further increase in Eu/Ce amount up to optimal concentration (1wt% Ce and 0.1wt% Eu) led to a decrease in the AB removal. The mineralization of AB using Eu-TiO 2 photocatalyst was confirmed by HPLC analysis.