Theoretical studies on the mechanism of oxygen reduction reaction on clean and O-substituted Ta3N5(100) surfaces
Theoretical studies on the mechanism of oxygen reduction reaction on clean and O-substituted Ta3N5(100) surfaces
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DOI：
10.1039/c5cy00088b
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发表时间：
2015-04
影响因子：
5
通讯作者：
Eriko Watanabe;H. Ushiyama;K. Yamashita
中科院分区：
文献类型：
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作者：
Eriko Watanabe;H. Ushiyama;K. Yamashita
从理论上探讨了氧还原反应(ORR)在Ta3N5(100)表面的反应机理。特别讨论了O-取代对催化剂活性的影响。首先，计算了氧分子在清洁和O-取代Ta3N5(100)表面上的吸附能和几何构型。然后研究了清洁和O-取代Ta3N5(100)表面上2电子和4电子反应的能谱。结果表明，氧分子在清洁的Ta3N5(100)表面上的吸附能几乎为零，氧分子更容易吸附在O-取代表面上。然而，OH和H2O在O-取代表面上有很强的吸附，因此它们的脱附可能是决定反应速度的步骤。为了提高ORR活性，O2和OH的吸附能都需要调整。通过对吸附质和Ta3N5O-取代表面的能级分析，发现Ta3N5的杂质状态是表征吸附能的关键指标。因此，可以通过改变杂质态的能量来控制ORR的活性。
The reaction mechanism of oxygen reduction reaction (ORR) on Ta3N5(100) surfaces was examined theoretically. In particular, the effects of O-substitution on the catalytic activity have been discussed. First, the adsorption energy and geometry of an oxygen molecule adsorbed on a clean and an O-substituted Ta3N5(100) surface were calculated. Energy diagrams for 2-electron and 4-electron reactions on clean and O-substituted Ta3N5(100) surfaces were then examined. The results show that the adsorption energy of an oxygen molecule on the clean Ta3N5(100) surface is almost zero and the oxygen molecule is easier to adsorb on the O-substituted surface. However, OH and H2O adsorb strongly on the O-substituted surfaces so that their desorption can be the rate-determining step. To improve the ORR activity, both O2 and OH adsorption energies should be tuned. By analysis of the energy level of adsorbates and Ta3N5 O-substituted surface, the impurity state of Ta3N5 is found to be the key descriptor for the adsorption energy. Therefore, the ORR activity can be controlled by changing the energy of the impurity state.