Synthesis-Dependent Oxidation State of Platinum on TiO2 and Their Influences on the Solar Simulated Photocatalytic Hydrogen Production from Water

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• 作者：Sreenivasan Koliyat Parayil ; Harrison S. Kibombo ; Chia-Ming Wu ; Rui Peng ; Trevor Kindle ; Srujan Mishra ; S. Phil Ahrenkiel ; Jonas Baltrusaitis ; Nada M. Dimitrijevic ; Tijana Rajh ; Ranjit T. Koodali
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：August 22, 2013
• 年：2013
• 卷：117
• 期：33
• 页码：16850-16862
• 全文大小：642K
• 年卷期：v.117,no.33(August 22, 2013)
• ISSN：1932-7455

文摘

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鈥揟iO₂鈥?%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鈥揟iO₂鈥?%C and Pt鈥揟iO₂鈥?%T consisted of similar compositions of PtO₂, these oxidized platinum species seem to appear further apart from TiO₂ in Pt鈥揟iO₂鈥?%C than Pt鈥揟iO₂鈥?%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.