Photocatalytic Hydrogen Production over CdS/Titania -nanotube Composite Films

摘要

Titania nanotubes (TiNTs) with high surface area were synthesized by hydrothermal reaction under strongly basic condition and their photocatalytic application was explored. After preparing a series of CdS-TiNT composite films with variation of the mole ratio (r) of TiNT/(CdS + TiNT), their photocatalytic activities for hydrogen production and the photocurrent generation under the visible light irradiation were examined. In the aspect of light absorption for the photocatalytic reaction, the CdS-TiNT composite films revealed similar amounts of absorption to their counterparts, I.e., CdS-TiO_2 particulate series. However, the former showed less significant synergistic effect in the photocurrent generation and lower photocatalytic activities compared to the latter. Consequently, it appears that TiNTs are not so effective photocatalyic material in spite of their larger surface areas rather than TiO_2 nano-particles, because they indicate a poor crystallinity and a less intimate interaction or contact with CdS particles owing to the tubular morphology and a readily agglomeration among themselves.