High pressure plasma treatment for controlling the surface activity and optical properties of TiO2 nanoparticles

The effect of high pressure radio frequency (RF) plasma treatment on TiO2 surface and photocatalytic property has been investigated. X-ray photoelectron spectroscopy (XPS) measurements have shown the two different oxidation states of oxygen in the untreated TiO2 powder. Its relative proportion changes with the different dose of plasma treatments. The proportion of Ti3+ surface states also changes after plasma treatment and strongly depends on combination of plasma power and treatment time. The photocatalytic activity of plasma-untreated and -treated samples was measured by observing the relative degradation of methylene blue. The result showed about 50% increase in photoactivity at the sample treated with 10 W RF power plasma. Low power plasma treatment is a more efficient process for achieving a photoactive surface. The effect of total dose (power and treatment time) and power has been also studied to modify the surface activity of TiO2 nanoparticles.