Metal-TiO2 Composite Nanofibers for Plasmon-Driven Photocatalytic Hydrogen Generation

We present the preparation of electronspun TiO₂ nanofibers co-decorated with Au and Pt nanoparticles. By using these composite nanofibers, we demonstrate the direct evidence of plasmon-enhanced hydrogen generation through through dual-beam irradiation. The Au/Pt/TiO₂ nanofibers exhibit certain activity for hydrogen generation under a single irradiation at 420 nm that excites the defect/impurity states of TiO₂. Significantly, when a secondary irradiation at 550 nm is introduced to simultaneously excite Au SPR, we observed 2.5 times higher activity for hydrogen generation. Further investigations by finely controlling the irradiation wavelengths reveal that the enhancement factor on hydrogen generation is directly correlated with the plasmon absorption band of the Au nanoparticles in the Au/Pt/TiO₂ nanofibers. The control experiments with different sacrificial agents suggest that the hot plasmonic electrons of Au are responsible to the enhanced photocatalytic activity that can be magnified when the semiconductor is simultaneously excited. Our observation and the enhancement principle would have impact to future plasmonic nanocomposite design for efficient solar energy conversion.