A first-principle study of the effect of vacancy defects and impurities on the adsorption of O2 on sphalerite surfaces
A first-principle study of the effect of vacancy defects and impurities on the adsorption of O2 on sphalerite surfaces
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DOI：
10.1016/j.colsurfa.2010.04.013
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发表时间：
2010-06
期刊：
影响因子：
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通讯作者：
Jian-hua Chen;Ye Chen
中科院分区：
文献类型：
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作者：
Jian-hua Chen;Ye Chen
采用基于密度泛函理论（DFT）的第一性原理计算方法，研究了氧在含空位和杂质的闪锌矿表面的吸附.计算结果表明，完美闪锌矿表面不存在O2吸附，而空位的存在（例如，Zn空位和S空位）和杂质原子（如Fe、Mn、Cu和Cd）对O2的吸附具有积极的促进作用。结果表明，O2在S空位表面的吸附能为−408.25kJ/mol，高于Zn空位表面的吸附能−218.55kJ/mol.对于Zn空位表面，O 2 p轨道与S 3 p轨道强烈相互作用，电子从S原子转移到O原子，导致S的氧化。对于S空位，O 2 p轨道与Zn 3d轨道强烈相互作用，电子从Zn原子转移到O原子，导致Zn的氧化.含Fe、Mn、Cu和Cd杂质的闪锌矿表面O2的吸附能分别为−181.40kJ/mol、−146.66kJ/mol、−95.53kJ/mol和−55.96kJ/mol，表明含Fe闪锌矿易氧化，含Cd闪锌矿不易氧化。氧分子在含Fe、Mn和Cd的闪锌矿表面上解离，而氧分子在含Cu的表面上不解离。S原子的3 p轨道和Fe、Mn、Cu原子的3d轨道向O原子的反键π 2 p轨道提供电子，增强了氧与闪锌矿表面的键合。然而，Cd原子的4d轨道提供较少的电子，这削弱了氧与表面的键合。
The adsorption of O2on a sphalerite surface with vacancies and impurities is investigated through first-principle calculations based on density functional theory (DFT). The calculated results show that O2adsorption is unavailable on perfect sphalerite surfaces, while the presence of vacancies (e.g., Zn-vacancy and S-vacancy) and impurity atoms (such as Fe, Mn, Cu and Cd) energetically favors the adsorption of O2. The results show that the adsorption energy of O2on a S-vacancy surface is −408.25kJ/mol, which is stronger than that of a Zn-vacancy surface at −218.55kJ/mol. For a Zn-vacancy surface, the O 2p orbital interacts strongly with the S 3p orbital, and electrons transfer from the S atom to the O atom, which results in the oxidation of S. For the S-vacancy, the O 2p orbital interacts strongly with the Zn 3d orbital, and electrons transfer from the Zn atom to the O atom, which results in the oxidation of Zn. The adsorption energies of O2on the sphalerite surface with Fe, Mn, Cu and Cd impurities are −181.40kJ/mol, −146.66kJ/mol, −95.53kJ/mol and −55.96kJ/mol, respectively, which indicates that Fe-bearing sphalerite is easily oxidized, while Cd-bearing sphalerite is not easily oxidized. The oxygen molecule dissociates on Fe-, Mn- and Cd-bearing sphalerite surfaces, while oxygen does not dissociate on the Cu-bearing surface. The 3p orbital of S and the 3d orbital of Fe, Mn and Cu atoms donate electrons to the antibonding orbital π2p∗of the O atom, which enhances the bonding of oxygen with the sphalerite surface. However, the 4d orbital of the Cd atom donates fewer electrons, which weakens the bonding of oxygen with the surface.