Semiconductor-metal nanocomposites are effective in facilitating photocatalytic processes. The coupling of semiconductor and metal nanoparticles provides a unique pathway for the discharge of electrons at the electrolyte interface.  The recent efforts to explore plasmon resonance effect to influence charge separation efficiencies in photocatalytic systems often undermine the electron acceptor properties of metal nanoparticles. The results presented here demonstrate that photocatalytically deposited Ag on TiO2 nanoparticles improve the photoelectrochemical performance of TiO2/Ag composite by capturing the photogenerated electrons and maintaining a more negative Fermi level.  The shift in the plasmon resonance of Ag shows that the charge equilibration between TiO2 and Ag is dependent on the irradiation conditions. The charging and discharging can be reversibly modulated through on-off cycles of UV irradiation.   These electron storage effects should be taken into consideration while evaluating the photocatalytic and photoelectrochemical properties of semiconductor-metal composites.

Role of metal Co-catalyst in semiconductor assisted photocatalysis: Charge equilibration vs. plasmonic effects

243rd National Meeting (2012)

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