Surface state of TiO 2 treated with low ion energy plasma

• Published in: Applied surface science Vol. 252; no. 10; pp. 3871 - 3877
• Main Authors: Jun, Jin, Shin, Joong-Hyeok, Dhayal, Marshal
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2006
• Subjects: Plasma; Surface modification; TiO 2; XPS; Plasma; Surface modification; XPS; TiO 2
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2005.06.004

The effect of low pressure radio frequency (rf) plasma treatment on TiO 2 surface states has been studied using X-ray photoelectron spectroscopy. Three different oxidation states of oxygen in untreated TiO 2 powder were observed, which suggests the existence of adsorbed water and carbon on the surface. The ratio of oxygen to titanium (O/Ti) was decreased for the low ion dose plasma treated samples due to desorption of water from the surface. In the case of Ti 2p about 20% of surface states were converted to Ti 3+ 2p 3/2 state after plasma treatment with a very good stability, whereas untreated TiO 2 remained mostly as Ti 4+ state. A rapid decrease in the ratio of carbon to titanium (C/Ti) at TiO 2 surface was also observed after plasma treatment and more than 90% of carbon atoms were removed from the surface. Therefore, the plasma treatment of TiO 2 has advantages to surface carbon cleaning, increasing O − and Ti 3+ surface states, hence improving the activity of TiO 2 for different environmental, energy and biological applications.