Papers by Author: Eun Ah Lee

Abstract: Cold spray process offers an oxidation-free atmosphere. It is usually used for TiO2 coatings used in photocatalytic applications to purify a given medium. Cold sprayed coatings with spray dried powder and evaporated powder were compared. Investigation of properties using SEM, XRD, roughness test were performed. SEM and XRD data were found to be very similar, however, variations were found for the surface roughness. Nano-sized powders were used in this investigation, therefore the coatings achieved were very thin in comparison to those from conventional powders, also they showed high uniformity.benzene removal from air by means of photoelectrocatalytic reaction was achived.

Abstract: Plasma spraying technique was used to deposit thin TiO2-based photocatalytic coatings on a foamed aluminum. Before spraying, the composites of nano-TiO2 powder (P25) and nano- ZnO/CeO2/SnO2 powders were agglomerated into microsized powders by a spray-drying process. XRD, SEM, TEM, XPS and the photocatalytic activity evaluation by the decomposition of benzene were applied to characterize the starting powders and the coatings, respectively. The results showed that all the three plasma sprayed TiO2-based coatings were the mixture phases of anatase and rutile. The XPS spectra results revealed that the oxygen element was composed of three kinds of chemical states, i.e., crystal lattice oxygen, hydroxyl oxygen and physical-adsorbed oxygen. The plasma sprayed 90%TiO2-10%CeO2 coating and 90%TiO2-10%SnO2 coating exhibited similar photocatalytic activity, which was higher than that of 90%TiO2-10%ZnO coating.