Efficient solar water splitting (or artificial photosynthesis) with suspended photocatalysts is the Holy Grail of clean energy as it could provide hydrogen (H2) as a renewable alternative to fossil fuels as a primary energy source. To this end, two promising materials for use as components in a tandem photocatalyst system were investigated. Main group element doped and non-doped bismuth vanadate (BiVO4) particles were synthesized and thin-films of the material prepared by drop-casting onto FTO substrates. Characterization by surface photovoltage spectroscopy revealed changes in electron injection into the FTO and the corresponding photovoltage signal in the modified samples relative to pristine BiVO4, implying differential effects of doping on majority charge carrier transport in the material. Additionally, the hydrogen evolving capacity of noble metal-enhanced, transition metal-doped strontium titanate (SrTiO3) was examined in the presence of methanol and a Fe3+/2+ redox couple. Activity toward hydrogen evolution in Ru/SrTiO3 under full spectrum irradiation was found to decrease with increasing Fe3+/Fe2+ ratio, due to the detrimental reduction of Fe3+ at the photocatalyst. For Pt/Ni:SrTiO3, the highest visible light activity was observed from materials in which Ni3+ was introduced by solid state synthesis rather than hydrothermal methods. High temperature synthesis reduces defects that can act as recombination centers for charge carriers. These investigations provide insights relevant to constructing an efficient tandem water-splitting device.

Photovoltage and hydrogen evolution studies on doped BiVO4 and SrTiO3 photocatalytic nanoparticles

2019 Spring National Meeting

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