Structures and energetics of H2O adsorption on the Fe3O4 (111) surface
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摘要: 使用密度泛函理论（GGA/PBE）对H2O在Fetet1-和Feoct2-终结Fe3O4 (111)表面的吸附行为进行了研究。对于Fetet1-终结表面，在1/5 ML覆盖度下，带有氢键的H2O分子以及异裂解离的结构具有最高的稳定性，而类似水合氢离子的OH3+-OH结构出现在2/5 ML覆盖度下，其次为带有氢键的水的聚合体。这些结果与实验中观测到的现象一致。对于Feoct2-终结表面，在1/6 ML覆盖度下，分子态H2O的吸附是有利的，而在1/3 ML覆盖度下多种吸附形式共存。H2O吸附在Fetet1-终结表面比吸附在Feoct2-终结表面热力学上更有利。此外，通过计算局域态密度（LDOS）对吸附机理进行了分析。
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关键词:
- Fe3O4 (111) /
- H2O /
- 吸附 /
- 密度泛函理论
Abstract: ater adsorption on the Fetet1-terminated and Feoct2-terminated surfaces of Fe3O4(111) has been calculated at the level of density functional theory (GGA/PBE). On the Fetet1-terminated surface at 1/5 monolayer (ML), the molecular adsorption mode with a hydrogen bond and the heterolytically dissociative mode show the highest stability, whereas the hydronium-ion-like structure OH3+-OH becomes possible at 2/5 ML, followed by the hydrogen-bonded water aggregate. These results agree well with the available experimental observations. For Feoct2-terminated surface, the molecular water prefers to adsorb on the surface Feoct2 atom at 1/6 ML, whereas other adsorption modes become possible and may coexist at 1/3 ML. The Fetet1-terminated surface is more favorable than the Feoct2-terminated surface for water adsorption. The adsorption mechanism has been analyzed on the basis of the calculated local density of state.-
Key words:
- Fe3O4 (111) /
- H2O /
- adsorption /
- DFT
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