Institute of Physics, Slovak Academy of Sciences, Dúbravská cesta 9, SK-84511 Bratislava, Slovak Republic.
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
J Chem Phys. 2017 Jul 28;147(4):044713. doi: 10.1063/1.4994701.
Nanoporous gold (NPG) prepared by de-alloying AlAu exhibits correlation between the high catalytic reactivity towards CO oxidation and the density of twinning defects in the fcc lattice of NPG. It was also discovered that on the internal surface of NPG, quite common twinning defects can create close-packed rows of six-coordinated catalytically active Au atoms denoted as W-chains. In this work, using density functional theory methods, we investigate energy conditions for formation, thermal stability, and chemical reactivity of these active sites. The possibility of dioxygen chemisorption on various surface sites is studied in detail. A contribution from the dispersion interactions is also considered. The calculated surface density of the active six-coordinated atoms in NPG comparable with that of supported gold nanoparticle catalysts, exothermic chemisorption of dioxygen, and the energy profiles of reaction pathways for CO oxidation indicate that the six-coordinated sites created by twinning can significantly contribute to the catalytic activity of NPG.
通过脱合金制备的纳米多孔金（NPG）表现出 CO 氧化的高催化活性与 NPG 的 fcc 晶格中孪晶缺陷密度之间的相关性。还发现，在 NPG 的内部表面上，相当常见的孪晶缺陷可以形成紧密排列的六配位催化活性 Au 原子列，称为 W 链。在这项工作中，我们使用密度泛函理论方法研究了这些活性位点的形成、热稳定性和化学反应性的能量条件。详细研究了各种表面位点上氧气的化学吸附的可能性。还考虑了色散相互作用的贡献。计算出的 NPG 中活性六配位原子的表面密度与负载金纳米粒子催化剂相当，氧气的放热化学吸附以及 CO 氧化反应途径的能量曲线表明，孪晶产生的六配位位点可以显著提高 NPG 的催化活性。
