Initial Oxygen Incorporation in the Prismatic Surfaces of Troilite FeS
Initial Oxygen Incorporation in the Prismatic Surfaces of Troilite FeS
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DOI：
10.1021/acs.jpcc.8b02774
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发表时间：
2018-05
期刊：
影响因子：
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通讯作者：
U. Terranova;C. Mitchell;M. Sankar;D. Morgan;N. D. de Leeuw
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文献类型：
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作者：
U. Terranova;C. Mitchell;M. Sankar;D. Morgan;N. D. de Leeuw
我们对氧化环境中硫铁矿的棱柱 (0110) 表面进行了理论研究，旨在阐明在磁黄铁矿 Fe1-xS 纳米粒子中实验检测到的氧的存在。我们发现原子氧吸附在 Fe-O-Fe 桥接基序中，这些基序在环境条件下是热力学稳定的。在第一个氧化步骤中，S-O 键的形成不如 Fe-O 键，这表明实验检测到的硫氧化物仅在随后形成。此外，我们预测硫取代氧是可能发生的。由于连续吸附而出现的 Fe-O-Fe-O-Fe 桥接图案表明氧化单元的聚集生长。与实验观察结果一致，硫铁矿的氧化是放热的，其中吸附和取代之间的平衡受到 Fe 空位的存在的影响。
We present a theoretical investigation of the prismatic (0110) surface of troilite in an oxidizing environment, which aims to elucidate the presence of oxygen detected experimentally in the pyrrhotite Fe1–xS nanoparticles. We find that atomic oxygen adsorbs in Fe–O–Fe bridging motifs, which are thermodynamically stable under ambient conditions. During the first oxidation steps, the formation of the S–O bond is less favored than Fe–O, suggesting that the sulfur oxides detected experimentally form only subsequently. We predict, moreover, that substitution of sulfur for oxygen can occur. The appearance of Fe–O–Fe–O–Fe bridging motifs due to successive adsorptions points toward a clustering growth of the oxidic units. In agreement with the experimental observations, the oxidation of troilite is exothermic, where the equilibrium between adsorption and substitution is influenced by the presence of Fe vacancies.