Photocatalytic hydrogen evolution with fibrous titania prepared by the solvothermal reactions of protonic layered tetratitanate (H2Ti4O9)

Various titania such as monoclinic titania, anatase and rutile were prepare d via the heat treatment of protonic layered tetratitanate. The microstruct ure and hydrogen evolution activity of titania changed significantly depend ing on the reaction conditions. Generally, the hydrogen evolution activity of titania prepared by solvothermal reactions in water and alcohols at 200- 325 degrees C was much higher than that prepared by calcination in air. The solvothermal reactions using methanol and ethanol were much more efficient in increasing the hydrogen evolution activity than when water was used. Wh en the titania formed by the solvothermal reaction in methanol was heated i n air, the hydrogen evolution activity decreased with increasing temperatur e; however, the powders possessed higher hydrogen evolution activity than t hose produced directly by calcining the protonic layered tetratitanate at t he same temperature without a solvothermal treatment. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.