Instability of Hydrogenated TiO2

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• 作者：Manjula I. Nandasiri ; Vaithiyalingam Shutthanandan ; Sandeep Manandhar ; Ashleigh M. Schwarz ; Lucas Oxenford ; John V. Kennedy ; Suntharampillai Thevuthasan ; Michael A. Henderson
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：November 19, 2015
• 年：2015
• 卷：6
• 期：22
• 页码：4627-4632
• 全文大小：417K
• ISSN：1948-7185

文摘

Hydrogenated TiO₂ (H-TiO₂) is touted as a viable visible light photocatalyst. We report a systematic study on the thermal stability of H-implanted TiO₂ using nuclear reaction analysis (NRA), Rutherford backscattering spectrometry, ultraviolet photoelectron spectroscopy, and X-ray photoelectron spectroscopy. Protons (40 keV) implanted at a 鈭? atom % level within a 鈭?20 nm wide profile of rutile TiO₂(110) were situated 鈭?00 nm below the surface. NRA revealed that this H-profile broadened toward the surface after annealing at 373 K, dissipated out of the crystal into vacuum at 473 K, and was absent within the beam sampling depth (鈭?00 nm) at 523 K. Photoemission showed that the surface was reduced in concert with these changes. Similar anneals had no effect on pristine TiO₂(110). The facile bulk diffusivity of H in rutile at low temperatures, as well as its interfacial activity toward reduction, significantly limits the utilization of H-TiO₂ as a photocatalyst.