Thermal Acceleration of Electron Migration in Gallium Oxide Photocatalysts

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• 作者：Katsuya Shimura ; Kazuki Maeda ; Hisao Yoshida
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：May 12, 2011
• 年：2011
• 卷：115
• 期：18
• 页码：9041-9047
• 全文大小：923K
• 年卷期：v.115,no.18(May 12, 2011)
• ISSN：1932-7455

文摘

In the photocatalytic steam reforming of methane (CH₄ + 2H₂O 鈫?4H₂ + CO₂) over gallium oxide (尾-Ga₂O₃), the hydrogen production rate increased with an increase of the reaction temperature before reaching ca. 343 K, and then it became constant. The pseudo-Arrhenius plot for the production rate in the lower temperature range showed a straight line, and the thermal activation energy was typically less than ca. 10 kJ mol^鈭?. The thermal activation energy varied with the irradiation light intensity, the crystallite size of Ga₂O₃, and the loading of metal cocatalyst. The lower thermal activation energy was given by the higher intensity of the irradiation light, the larger crystallite size of Ga₂O₃ particles, and the larger particle size of the cocatalyst, whereas the higher one was given by the surface defects and/or the cocatalyst alloying. These facts suggest that the thermal energy would promote the migration of photoexcited carriers both in the bulk of Ga₂O₃ and at the metal鈭抯emiconductor junction between the metal cocatalyst and Ga₂O₃.