Evidence of atomic adsorption on TiO2 under plasma exposure and related C2H2 surface reactivity
Résumé
Adsorption/reaction kinetics of C2H2 on the surface of plasma-treated SiO2 and TiO2 catalysts is studied. The catalysts are pretreated with a dc discharge in Ar, O2, N2, or air. Then 950 ppm of C2H2 in air is introduced in the closed-volume reactor. It is found that TiO2 pretreated with O2 or air plasma catalyzes C2H2 removal from the gas phase without any UV activation. During 10 min after introduction the loss of C2H2 in the whole reactor is about 5×1015 molecules. Comparison between different pretreatment procedures shows that weakly bonded oxygen atoms may remain on TiO2 long after plasma exposure