Transition metal doped large band gap semiconductors are of interest as potential photocatalysts for the visible light driven water splitting reaction. We have synthesized cubic SrTiO3 45 nm nanocrystals through one-step hydrothermal method. Different amounts of Cu, Fe, Mn and Ni cations were doped into the lattice by adding corresponding metal salts into the reaction mixture. The optical properties, effective bandgap and photochemical charge transfer of the nanocrystals are revealed by employing surface photovoltage spectroscopy (SPS) as a contactless technique with high sensitivity to measure photo-driven potential. All dopants insert energy levels within the SrTiO3 bandgap and promote the absorption of visible light, which leads to earlier photovoltage onset and greater voltage size. In spite of this, the visible-light induced photocatalytic activity, measured by hydrogen evolution with sacrificial agents and cocatalysts in suspension is not significantly increased in comparison to non-doped SrTiO3. Reasons for discrepancy between photovoltage and catalytic activity will be discussed in the talk. Overall, this work sheds new light on the factors that control photochemical charge transport and photocatalytic reactions at nanocrystal surfaces.

Photovoltage, effective bandgap and photochemical charge transfer in nanoscale transition metal (Cu, Fe, Mn, Ni) doped SrTiO3 photocatalysts

253rd National Meeting (2017)

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