Comparison of the photocatalytic activity of Fe–C doped mesostructured TiO2 films in a microreactor

Abstract

Carbon and iron co-doped titanium dioxide films were successfully synthesized using an environmentally friendly methodology that avoids surfactants and high calcination temperatures. The photocatalytic activity of these films was evaluated in a continuous flow planar microreactor under simulated sunlight, using 4-chlorophenol as the model pollutant. Different thermal post-treatments at 150 ◦C and 400 ◦C were tested to evaluate their effect on catalyst activity. Characterization techniques were employed to determine the optical and structural properties of the films. The highest degradation rate (6.99 × 10− 12 mol cm− 2 s − 1) and quantum efficiency (1.08 %) were achieved with the film doped with carbon and iron that underwent thermal post-treatment at 150 ◦C (FeMT–150). These values were almost eight times higher than those of the undoped film. The degradation percentage of 4-chlorophenol was sustained after 20 h of using the FeMT–150 film, which also allowed for the partial mineralization of the organic pollutant. The mild heating temperature would promote the diffusion of carbon and iron into interstitial and substitutional sites of the titania matrix, generating new electronic states that retard the recombination of electrons and holes in the catalyst, thereby enhancing catalyst efficiency. The performance of the immobilized catalysts aligns with previously reported activities of the same materials in slurry systems. This study marks a step toward the application of photocatalytic films at large scale.