Platinized TiO2 photocatalysts of different compositions of Pt0 and PtO2 were prepared by modifying the synthesis procedures. The physicochemical properties of the composite materials were characterized by X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. Energy dispersive X-ray spectroscopy measurements confirmed the presence of Pt species existing as PtO2 and/or mixtures of Pt0 and PtO2. The composite material, Pt-TiO2-2%H, contained a high amount of metallic Pt0 and PtO2 in close proximity with TiO2 that promoted an enhanced photocatalytic hydrogen evolution activity under simulated solar light irradiation. Although Pt-TiO2-2%C and Pt-TiO2-2%T consisted of similar compositions of PtO2, these oxidized platinum species seem to appear further apart from TiO2 in Pt-TiO 2-2%C than Pt-TiO2-2%T. This caused dramatic variation in their optical behaviors such as strong fluorescence quenching and lower photocatalytic hydrogen evolution activity in the former photocatalyst. A photocatalyst prepared by the conventional photodeposition method was also prepared, characterized, and its photocatalytic activity assessed. This work provides an opportunity to understand the role of PtO2 for photocatalytic production of hydrogen from platinized TiO2 composites and the importance of heterojunctions in such photocatalysts for solar energy conversion.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films