Photocatalytic Hydrogen Production from Gas-phase Methanol and Water with Nanocrystalline TiO_2 Thin Films in High Vacuum

摘要

Photocatalytic hydrogen production with gas-phase reactions in high vacuum was examined for nanocrystalline anatase-type titanium dioxide (TiO_2) thin films. The hydrogen generation process on platinized TiO_2 specimens was investigated using a quadrupole mass spectrometer at a real-time scale under various partial pressures of gaseous methanol and water. As a result, hydrogen generation was successfully detected under ultraviolet (UV) ray illumination even in high vacuum (～10~(-7) Torr). And the amount of produced H_2 largely depends on the temperature of TiO_2 samples, probably due to different surface states of TiO_2. This study suggests the possibility of new high-speed H_2 production system with gas-phase photocatalytic reactions.