The surface nature of Li_2TiO_3 and the adsorption behavior of water on Li_2TiO_3 surface were studied by XPS/UPS and FT-IR. Preliminary experiments by Ar ion sputtering, heating and water exposure were conducted, and the following results were obtained. (ⅰ) By Ar sputtering, Li deficient surface was made, and Ti was reduced from Ti~(4+) to Ti~(3+). (ⅱ) By heating sputtered samples over 573-673 K, Li emerged on the surface and Ti was re-oxidized to Ti~(4+). The surface -OH was removed. The valence band of Li_2TiO_3 became similar to that of TiO_2. (ⅲ) By water exposure at 623 K, H_2O could be adsorbed dissociatively on the surface. LiOH was not formed. (ⅳ) The nature of Li_2TiO_3 surface resembles that of TiO_2, rather than Li_2O.
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