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采用自旋极化密度泛函和广义梯度近似的方法并结合周期平板模型, 探讨了不同覆盖度(θ)下双金属簇X (X=Pt-Au, Au-Au)在(3×2)TiO2(110)完整表面上的吸附行为. 另外, 在本文给出的所有覆盖度模式下(θ=1/6-1 ML), 我们仅研究其基态构型. 计算结果表明: 当θ<1/2 ML 时, 金属簇 X 在 TiO2(110)表面上吸附能随覆盖度的增加而增加; 当θ>1/2 ML时, 除了饱和覆盖度下, 吸附能随覆盖度的增加而减小; 当θ=1/2 ML时, 吸附能最大. 即使Pt-Au/TiO2体系的吸附能比Au-Au/TiO2体系的小, 但相对于Au-Au簇, Pt-Au簇更容易在TiO2(110)表面上形成双金属单分子层. 在半覆盖和全覆盖下, X簇的峰与TiO2的峰在-3.0 eV到费米能级之间产生明显重叠, 表明簇与底物之间存在化学作用. 且当覆盖度小时, X-TiO2相互作用是成簇的主要因素; 随着覆盖度的增大, X-X原子间相互作用就逐渐变成了成簇的主要动力.
The spinodal density functional theory and generalized gradient approximation are used in combination with the periodic plate model to investigate the effect of the bimetallic clusters X (X = Pt-Au, Au-Au) on the (3 × 2) In addition, we study only the ground state configuration for all coverage modes given in this paper (θ = 1 / 6-1 ML). The calculated results show that when θ <1 / 2 ML, the adsorption of metal cluster X on the surface of TiO2 (110) increases with the increase of the coverage. When θ> 1/2 ML, the adsorption energy decreases with the increase of the coverage except the saturation coverage , And the adsorption energy is the largest at θ = 1/2 ML. The Pt-Au clusters are more easily deposited on TiO 2 than Au-Au / Au clusters even though the adsorption energy of Pt-Au / Forming a bimetallic monolayer on the surface of the substrate 110. Under both semi-coverage and full coverage, the peaks of the X clusters and the peaks of TiO2 produced a significant overlap between -3.0 eV and the Fermi level, indicating that between cluster and substrate There is a chemical reaction, and when the coverage is small, X-TiO2 interaction is the main factor of clustering. With the increase of coverage, the interaction between XX atoms gradually becomes the main driving force of clustering.