摘要:
采用密度泛函理论和平面波赝势方法对含天然杂质黄铁矿的电子结构和光学性质进行了计算,并讨论了二十种天然杂质：钴、镍、砷、硒、碲、铜、金、银、钼、锌、铊、锡、钌、钯、铂、汞、镉、铋、铅和锑,对黄铁矿催化活性的影响.结果表明在过渡金属杂质中,杂质能级主要由它们的d轨道产生,而在主族金属及非金属杂质中,杂质能级主要由它们的s或p轨道产生.含铜、钼、砷、金、银或镍的黄铁矿对氧的还原的电催化能力增强.除锌、钼、钌、砷、锑、硒和碲外,其余杂质能增强黄铁矿表面俘获电子的能力,使光生电子和空穴复合的概率减小.光学性质计算表明,除镉、汞、钌、硒、碲和锌杂质对吸收带边影响不大外,其余杂质使黄铁矿的吸收带边发生了红移,特别是含金和银杂质黄铁矿的吸收系数增加了两个数量级.
Abstract:
The electronic structures and the optical properties of pyrite containing twenty natural impurities, Co, Ni, As, Se, Te, Cu, Au, Ag, Mo, Zn, Tl, Sn, Ru, Pd, Pt, Hg, Cd, Bi, Pb and Sb, are investigated using the density functional theory and the plane wave pseudopotential method, and the catalytic activity of pyrite is discussed. For the transition metal-bearing pyrite, there are introduced impurity energy levels in the band contributing from impurity d orbital, while for the other metal and non-metal-bearing pyrite, the impurity energy levels are contributed from impurities s or p orbital. The presences of Cu, Mo, As, Au, Ag or Ni can enhance the electrocatalytic ability of pyrite to the oxygen reduction. All the impurities, except Zn, Mo, Ru, As, Sb, Se and Te, can enhance the ability of pyrite surface to capture electrons and hence the recombination rate of photoinduced electrons and holes wile be reduced. Calculations of optical properties indicate that Cd, Hg, Ru, Se, Te and Zn impurities each have small influence on the absorption band edge, while the presence of other impurity makes a red shift of absorption band edge of pyrite. Especially, the presences of Au and Ag impuritie increase the adsorption coefficient of pyrite by two orders of magnitude.
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