tunable charge transfer and dual plasmon resonances of au@wo3−x hybrids and applications in photocatalytic hydrogen generation

We synthesized au@wo3−x hybrids with dual plasmon resonances in visible and near-infrared (nir) regions induced by two counterparts for enhancing photocatalytic activity. au cores slightly influence hetero-morphology, significantly modify semiconductor plasmon, and prominently enhance h2 generation of wo3−x shells. as atom ratio of ρw:au increases from 2 to 10, visible plasmon resonance is weakened with peak blueshifting from 540 to 490 nm, while nir plasmon resonance strength prominently increases, and eventually average enhancement factor of photocatalytic h2 generation of the au@wo3−x hybrids with white light illuminations increases from 1.76 to 2.85. furthermore, the wavelength dependence of h2 generation reveals that the dominant physical mechanism of enhancing the photocatalytic activity of the hybrids is varied from excitation energy transfer to electron transfer from au cores to wo3−x shells as ρw:au increases. the construction of this metal-semiconductor hetero-nanostructure with dual plasmon resonances has immediate importance for the applications in solar energy conversions.