Thermal Acceleration of Electron Migration in Gallium Oxide Photocatalysts
Thermal Acceleration of Electron Migration in Gallium Oxide Photocatalysts
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DOI：
10.1021/jp110824n
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发表时间：
2011-04
影响因子：
3.7
通讯作者：
Katsuya Shimura;Kazuki Maeda;H. Yoshida
中科院分区：
文献类型：
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作者：
Katsuya Shimura;Kazuki Maeda;H. Yoshida
在氧化镓（β-Ga 2 O3）催化甲烷水蒸气重整反应（CH 4 + 2 H2O → 4 H2 + CO2）中，在达到约100 ℃之前，产氢速率随着反应温度的升高而增加。343 K，然后它变成常数。在较低的温度范围内，生产速率的伪Arrhenius图显示为直线，并且热活化能通常小于ca。10 kJ mol−1。热活化能随辐照光强、Ga_2 O_3晶粒尺寸和金属助催化剂的负载量而变化。较低的热活化能是由较高强度的照射光，较大的晶粒尺寸的Ga 2 O 3颗粒，和较大的粒径的助催化剂，而较高的一个是由表面缺陷和/或助催化剂合金化。这些事实表明，热能将促进光激发载流子在Ga_2O_3体中以及在Ga_2O_3与Ga_2O_3之间的金属-半导体结中的迁移。
In the photocatalytic steam reforming of methane (CH4 + 2H2O → 4H2 + CO2) over gallium oxide (β-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−1. 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−semiconductor junction between th...