Direct evidence of plasmon enhancement on photocatalytic hydrogen generation over Au/Pt-decorated TiO2 nanofibers

Abstract

Direct evidence of plasmon-enhanced H₂ generation is observed in photocatalytic water reduction by using TiO₂ electrospun nanofibers co-decorated with Au and Pt nanoparticles through dual-beam irradiation. The Au/Pt/TiO₂ nanofibers exhibit certain activity for H₂ generation under single irradiation at 420 nm that excites the defect/impurity states of TiO₂. Significantly, when secondary irradiation at 550 nm is introduced to simultaneously excite Au SPR, we observed 2.5 times higher activity for H₂ generation. Further investigation by finely controlling the irradiation wavelengths reveals that the enhancement factor on the photocatalytic activity for H₂ 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 for the enhanced photocatalytic activity that can be magnified when TiO₂ is simultaneously excited.