Low-temperature atmospheric pressure plasma deposition of TiO2-based nanocomposite coatings on open-cell polymer foams for photocatalytic water treatment

An aerosol-assisted plasma process was used to deposit, at low temperature and atmospheric pressure, photocatalytic hydrocarbon polymer/TiO2 nanoparticles nanocomposite coatings onto both flat glass slides and open-cell polyurethane foams. Various characterization techniques were used to demonstrate the potential of the developed process for the controlled deposition of TiO2-based coatings on the different supporting substrates, with special attention to the foams due to their complex three-dimensional porous structure. The photocatalytic activity of the plasma-coated materials was evaluated by the decomposition of methyl orange in aqueous solution under UV irradiation, using a purposely designed recirculating batch photoreactor. The comparative study revealed that greater photocatalytic activity can be achieved with the open-cell foams, pointing to the beneficial properties of macroporous photocatalyst supports in comparison with conventional flat ones. The prepared photocatalytic materials presented remarkable reusability and maintained good activity after prolonged operation (40 h) corresponding to 20 consecutive reaction runs. Results on the evolution of the photocatalytic performance of the plasma-coated samples over multiple runs were correlated with those obtained from the detailed characterization of their surface chemical composition, morphology and wettability as a function of the operation time in photocatalytic water treatment.